MJNewton

The plinth cutout is to prevent it fouling the dishwasher door. Without that hole most dishwashers couldn't be fully opened (or, if installed already open, couldn't be closed!). I'd take the dishwasher out (integrated doesn't mean not removable!) and seal along the gaps at source with sealant (anything would do - silicone, caulk etc) or foam if large enough. Might you need to go under/behind other cupboards too?

System boiler means unvented whereas regular (heat only) means vented which is what they have now. Not necessarilly. We've hot a heat-only boiler with an unvented cylinder and CH system. A heat-only boiler - as the name implies - just provides heat and so you need external components (pump at a minimum but also valves if more than one circuit) to incorporate it into the wider system. In addition to gas and (if a condensing boiler) condensate drain, it has a single a flow and return. A system boiler has the pump built-in and separate flow and returns for CH and HW. Vented vs unvented is an orthogonal issue not tied to heat-only vs system boiler type, but specific boilers may be designed to only work with one or the other.

Now that we’ve got cooler outside temperatures, what are the temperatures of the supplied air like? It should be obvious if the summer bypass is activated.

We've got the Hybalans+ Conus Air Valves: No adjustment at the terminal and so require throttling at the manifolds instead. In all honesty whilst I put a lot of effort into choosing terminals I liked I must admit we just don't notice them anymore - they just end up blending in with the surroundings once your mind ends focused on things other than the MVHR installation!

Yeah, I bet even after only a few hours it'd be fine for a cat to walk carefully on. If sand and cement it is pretty dense and tampered down. Of course, cats being cats, they'll chase a mouse around on it, dig holes etc, so I'd keep it away for a day just to be sure.

One day you'll be thanking him... 😁

Deeper the better is my preference, within reason of course! Gives more room for smart relays, dimmer modules, easier/neater wiring etc. Also far better for them to be too deep than too shallow thus require retrospective remedying!

Ours is on a wall in the loft (above a bedroom) and I opted to effectively sit ours on some rubber exhaust hangers to provide some isolation from the building. We don't hear it, but that doesn't mean it was necessarily necessary as we didn't try it mounted direct!

It looks daunting but I promise it's quite straightforward... If you go in to the Shelly app and select a sensor you should be able to configure it, one setting of which will be a menu related to actions or something similar like the following:

I suspect the 'Addon Sensors' section on the 1PM is intended for directly connected sensors, whereas what you've got are remote sensors. That's not a problem though; they can send commands over the network. I've not used a Shelly Motion sensor before but I am assuming there's a setting somewhere that can trigger a URL call when motion is detected. In here you need to put something like the following on each of the sensors: http://<ip.address.of.1pm>/relay/0?turn=on&timer=60 (where 60 is the time in seconds that you want the pump activating for) There are further details in the published API but that ought to be enough to at least get things going.

It's not more the surrounding piperwork (and/or pump, if present) is it? Normally UVCs are so well insulated that they don't tend to emit much heat. Does no harm adding more insulation I suppose though, and of course if you've already got it!

If concerned about the thermostat could you just leave a gap for it in the jacket? That said, is it really worth insulating it more than it already is?

If you're in a position to test it straight away then Amazon's return's policy/process is second to none if there are any issues.

@Ultima357 did a great write-up of a DIY actrive carbon filter with seemingly really positive results...

Looks perfect! Personally I wouldn't worry about branding.

Sorry, should've caveated the suggestion with the admission that I only found it through Google! I see there are some online sellers (in Poland, example) but they seem to limit shipping to the EU. Could maybe get it sent via someone over there (involving your perhaps!).

How complex is the existing building and proposed extension? If fairly run of the mill then I wouldn't want to be paying (extra) for an 'Architect' - I'd be more than happy for an Architectural Technician (which is the title I am most familiar with, but which is presumably synonymous with 'Architectural Technologist' that George mentioned). Aside from being cheaper they might also be a bit more down to earth (no offence intended to any resident architects!).

How about this if you can find a stockist? Hard to imagine anything smaller really!

Entirely your prerogative, and a reasonable position to take. Other BCOs may take a different view and be perfectly content with it, and they'd be no less right or wrong than you in doing so. The BRs simply aren't specific enough to be able to draw a specific line on this, and their aim is only reducing risk to a 'reasonable level' - not completely eliminating it otherwise we'd also be discussing the need to put in measures to stop people putting wood-filled wicker baskets on their hearth (raised or not! )...

Yes, and on that I think we're in complete agreement. Here are the BRs on the subject: I can perfectly understand a BCO being content with a non-combustible finished flooring surface and construction not requiring a raised hearth.

Comply with what exactly? You shouldn't conflate Approved Documents with the Building Regulations. The ADs merely offer practical guidance on how the BRs can be met which, generally (but not always) speaking, means that if you follow the ADs then there is a presumption of compliance with the BRs. Following the ADs makes the BCO's job relatively straightforward, however they are always in the position of allowing consideration of alternative approaches which, if they are content still meet the provisions of the BRs (which are very high-level and not detailed like the ADs are), can be accepted and signed off as such. There is nothing in the BRs that explicitly requires a change in level.

That falls to Diagram 26: And the corresponding text in particular: 2.26 An appliance should be located on a hearth so that it is surrounded by a surface free of combustible material as shown in Diagram 26. This surface may be part of the surface of the hearth provided in accordance with Paragraph 2.23, or it may be the surface of a superimposed hearth laid wholly or partly upon a constructional hearth. The boundary of this surface should be visually apparent to provide a warning to the building occupants and to discourage combustible floor finishes such as carpet from being laid too close to the appliance. A way of achieving this would be to provide a change in level.

You don't need it. It's only required when fitting directly into a thin sink e.g. a pressed metal sink that would otherwise flex when operating the tap.

No, the bushes you showed have the wrong male/female orientation (they fit into a 1/2" female and accept a 3/8" male bit you've got a 3/8" female on the end of your tap connector).

Apologies - I screwed up the link. Here it is again.