JohnMo

To me if have fibre, you have fibre connection. It not a new site, it's just a new house, on an old site

Large bifacial PV panels? If wood, vertical slates not horizontal. Think stairs balustrade not fence. It also has to satisfy wind load requirements, impacts and not fall over. These requirements change with fall height. Look up balustrade requirements.

So are you planning electric UFH in the house? Sounds expensive to run.

If your anywhere near there on a new build, something is well wrong. UFH the parts are cheap enough. Your heat pump doesn't need to cost much either, mine was £2100 including VAT, you can claim the VAT back on new build. I would do a direct cylinder and just do cheap rate water heating, a cylinder is about £500. Then it's a matter of sourcing the fan coils. One in each bedroom. If you want to run fan coils at low temp for cooling you need condensation drains on fan coils and an electronic mixer, other option (the sensible one) run it at same temp. Your most expensive bit is the fan coils. If that's the fall back, why are you being anal about cooling - be pragmatic install A2W simply as above and actually have cooling. (Don't bother getting ripped off by a grant scheme)

If doing as above the normal thermostat doesn't comply as it has to be non self resetting, a dual function cylinder thermostat would comply or a stand alone non- self resetting one complies That is indeed one way to achieve compliance, but not the only way. From G3 Regs The selection of safety devices should take account of the physical location of the devices, and the design, confguration, location of components and performance characteristics of the system to which they are attached. 3.18 An acceptable approach might consist of: a. a non self-resetting energy cut-out to disconnect the supply of heat to the storage vessel in the event of the storage system over-heating; and b. a temperature relief valve or a combined temperature and pressure relief valve to safely discharge the water in the event of serious over-heating. Alternative approaches to this are acceptable provided that they provide an equivalent degree of safety. Unvented hot water storage systems – systems up to 500 litres capacity and 45kW power input 3.21 If an indirect supply of heat to an unvented hot water storage system incorporates a boiler, the energy cut-out may be on the boiler. Narrative from me. As a heat pump cannot achieve high enough temps to allow boiling of the water (even R290 can't get hot enough) a primary control is there by default. If the heat pump uses an inbuilt immersion that immersion has to have a non- self reset thermal cutoff to comply with regs For the regs a heat pump is a boiler. Diverter valves - To comply with G3 Building Regulations. When installing with an unvented cylinder, Port A must be used for the hot water connection to the cylinder heat exchanger and Port B for the central heating connection. This means the valve when de-powered shuts the flow to the cylinder.

Yes

If you are getting mould its really a ventilation issue that needs to be resolved. You will get two camps of answers here, but I didn't and would bother with UFH under shower or a bath

Why would you be doing an S plan with a heat pump? That isn't the way to do heat pump plumbing, maybe ok for a boiler, but still wouldn't go that route. You should be using a diverter valve, which is your positive energy cutout. Primary pipe from heat pump, to diverter valve, normally open route to CH and the normally closed to the cylinder. The diverter is controlled via ASHP controller on a demand for cylinder heating. ASHP ramps flow temp up for cylinder heating. Your ASHP is equipped with the safety features to only need that.

But that is real life. Your reinstatement is based on normal terms, not self builder, buying carefully, working long days efficiently etc. Realistic pricing is £2500/m² possibly more depending on spec.

Sounds pretty weak. If you want a stronger version but also insulated use Compacfoam. Make it deeper than 20mm by doing a double layer glued and screwed together.

Maybe not, A2A is ok for £2.5k only and almost no one is approved, so don't hold your breath on that one. If you assume UFH is just part of house build cost. It all doesn't have to cost a lot to build a good performance system. I never bothered with the grants, would rather pay myself than get ripped off. Simple direct UVC for DHW, cheap as chips, save around £1000 compared to pre plumbed heat pump one. Charge on time off use tariff. Would be surprised if you need more than a 4kW heat source, from size of house and assuming better than Building Regs. If you want Aircon performance add a mixing valve to system and run fan coils at 6 degs, or just oversize the fan coils, decent fan coils have the output data for different flow temps. Or do everything A2A, don't bother with UFH. Still do direct water heating. Spend the money saved on a good system with good airflow regulation. Having lived in hot countries a number of years, the airflow became a thing of hate, once the novelty wore off.

The F gas solution doesn't look cheap, may be wrong. Could be a good system, but I would go A2W and have fan coils (water to air) in bedrooms and normal wet UFH. A pragmatic design could be pretty simple. Design for heating, accept cooling may not be perfect but way better than not having cooling. UFH will make house feel way cooler than the air temperature is. The fan coils in bedrooms will leave rooms for a comfortable sleep. First job is looking at heat loss and sizing an outdoor unit. Then room by room heat loss. Design UFH (not some cut and paste job by UFH suppliers). Size fan coils to provide room heating at under 30 degs. Then run everything as a single zone. Fan coils will modulate fan speed to keep room temperature stable. The above assumes you are talking about a low energy house.

Just looked at cost of flexible stick down panels - scary prices.

I am using Axle VPP. 3 events this month so far.

Generally a thin film technology with a 15 year life. But can perform better than mono crystalline in low light conditions. But worth now days, most likely not. We runs ours on Cosy tariff, so you can actually size to meet just under 1/3 of peak winter consumption, as you get cheap periods to run house and charge the battery. Rest of the year I just charge to 60% and it does fine, never discharged low and never fully charged to help life of battery. We are paying 10p kWh instead of near 27-30p. Plus get a compatible battery to allow you to join a VPP scheme (virtual power plant) and earn £1 per kWh on export events. Helps justify pay back a little better.

Solar and efficiency isn't really that important, it's just a measure of output compared to possible irradiation. So panels are bigger compared to 25% efficiency. As long as you have space, no issues. From what I have seen price wise not a cheap solution - but maybe your only solution. Will you get payback? Maybe a long one. Would just a battery give a better bang for the buck? - possibly.

Think the issue is not you, just shows the lack of attention to detail, by so called trades people. How things look and are balanced is important. We had to get a couple ceiling lights moved, they didn't align with anything and looked crap.

He did say he was building a big house, maybe its really really big and got a side extension. Maybe its that new build castle on Grand Designs

It always made me laugh using stainless bolts / screws with the aluminium clamps as used in a approved kits. From a materials perspective it's a disaster waiting to happen. Aluminium and stainless are not best of friends. Aluminium being a sacrificial anode to stainless.

I would place it well away from house, not sure how your house insurance would react to a house fire caused by self install car battery to house using YouTube instructions? Is the price savings even worth the effort these days, plenty of cheap battery setups available.

Some basics here https://www.theglasgowlawpractice.co.uk/at-what-point-is-a-house-sale-legally-binding-in-scotland-from-making-an-offer-to-concluding-missives-learn-about-property-purchase-in-scotland/ Saying beware, be sure your missives are signed before getting carried away.

Not quite correct, you need signed missives by both parties to fully legally binding. And this only gets done at the end of proceedings now - it used to be done at the start of proceedings. So don't count on it.

Could he also sell if a better offer came along. Would suspect his and your solicitor will come up with a very different scheme.

You need to get get bait boxes and suitable bait, get rid the problem, they will be your warm house next

VCL goes at the bottom. Between the insulation and concrete you can put a thin polythene layer, as mentioned above to keep concrete out of the insulation, if it gets in your insulation will float up.