Thanks all! Unfortunately it's not really possible to notmodernise fairly soonish. I don't think the house has been touched since it was built (20s/30s), which means electrics are really old and the house needs to be re-wired, which in itself is a large job so we may as well do some internal work at the same time. I'm warming to the idea of a shower room downstairs, but I can't see where it would fit. We'd be keeping the doorway out to the side, but I think it'd be weird to walk into a shower room from there. Preferably you'd walk into the utility and the shower room would be off that, but I just can't figure it out floor plan-wise. Any ideas? titiankim - well spotted RE the windows in the rear reception. There's actually a window on the right leading towards the current "garden room" and there are two internal windows too. Funnily enough the rear reception room is really light currently. If we went with the sketch I drew, we'd keep it so that there are windows going all the way around that side and into the kitchen/diner. I also like the idea of keeping the two internal windows, plus the double doors to the kitchen would have windows too, so it'd still be quite bright. I think it's a wise idea to keep both reception rooms as I do think my mother's partner and his father would like their own space (plus the rear reception would make a great play room for future families). I've attached a photo of this room so you get a better idea.

Thanks for your help and advice- all really useful and helping me sort the confusion of what I need and want and what is and isn't possible. The skinny space is the kitchen now. It's not ideal as of course is very small and narrow so can't house much. But I like that it's just off the reception room and. It quite in it! The kitchen houses the boiler currently and all pipe work there for oven and sink etc so I know this can be the kitchen but just worried the space is too small. My original plan was to keep the kitchen where it is but rehouse boiler and put washing machine in the toilet. The toilet would go in the bathroom but of course now that's not possible I need to put the boiler and washing machine somewhere and if back in the kitchen then I lose so much space. Could such a small space work? I need to rule out this ideal by speaking to a specially that deals with very small spaces. Any recommendations please?

This is a very crude attempt at subtly changing your plans. It would require more internal modification to move a wall which you may not consider worth it but I wondered whether the utility would be better as a longer and narrower room to incorporate outdoor access (for laundry, muddy feet / boot room, etc) rather than having outdoor access from the study with the wasted ‘corridor’ past the bathroom. This would also make a wider second living space which could have double doors to link it to the lounge so that you could open it up for larger family occasions or close it off for smaller events / everyday.

The best advice I have ever received was to live in a house/flat first for at least a year before doing renovations/extensions. You don't know how it feels, how the light tracks through the space through the day and many other factors. I can appreciate wanting to get the work done before moving in but if it is to be your home then you need to make good decisions for such a large investment. I would find an architect and discuss what you are planning so that you get the best possible outcome.