Thank you @JohnMo and @Redbeard for the messages. The orientation is the frontage you see in the photo is south facing. It's nearly perfect south.
Perhaps I should have explained. The house needs "gutting" because everything internally is really old. Artex ceilings, textured wallpaper, exposed central heating pipes, kitchen units falling apart, non existent wall sockets upstairs with old grey style metal consumer unit that is not fit for modern age. It will need full rewire and full new plumbing, new kitchen, new flooring, new everything.
We're a family of five living here with three young children and we need to modernise our home. We bought it with the view of extending. Two of our children are special needs. Our 9 year old son is profoundly Autistic with high needs and will be living with us for the rest of our/his life. We're looking to add a sensory room for him. We will also potentially have grandparents move in once extended as they currently travel in every day to help out with the children and taking them to and from school. Me and the wife are both working full time. That's the reason why we're looking to increase the size of the house as much as we can. Also we need to alter the living space to open plan as we need to oversee the children and have line of sight. Our boy can really go for our toddler if he feels annoyed or any noises are made. 😩
In terms what would be a priority is renovation>extension> energy efficiency (insulation, air tightness, solar and battery for bill savings). The aim is to do it once, do it as best we can and we chose to wait and do it this way instead of having a mish mash of renovation and constant upheaval where you're doing a bit at a time. We're lucky that some years down the line after buying we can afford to do this now without putting ourself out financially.
The drawings posted are just for submitting planning and not detailed. I will be having detailed construction drawings from my architect once we get the planning accepted.
In terms of insulation the only old fabric of the house will be the frontage you see there. and the wall of the existing side extension of ground level. Hoping to do some trial holes and hopefully the foundations are good enough to add the second story on top. The house is definitely solid brick. The existing side extension is cavity wall from the 90s I expect (previous owners built it). I'll have to see if there's any existing insulation within it. I am mindful of this but I'm hoping to fill that cavity with beads. The access road is shared road for garages so strictly speaking I'm not allowed to put anything on the side externally but realistically maybe just 50mm EWI may not ruffle any feathers. The main neighbour that has most of the impact said he was fine with it.
From our calculations we have the funds to do the renovation and extension as seen on the drawings and that is the priority. But with what would be left over also we like to get the best cost/benefit analysis in terms of energy efficiency/insulation and eco friendly aspects to our build. Currently we're hoping to not get a loan out but if something is worth is we will.