I think I'm writing this to clear it in my head more than anything else.
Own property that we want to single storey extend and remodel downstairs. Will need to remortgage to pay for it to the tune of 120k. It will do us until we go out in a box.
We've already done bathrooms, kitchen, boiler, drive, garden, etc.
Current value 340k, likely to increase to 385k after works.
Negatives are that if we did subsequently decide to sell we'd have much less equity to use for the next purchase and we're late 40s so mortgage term would be short and payments expensive.
Positives are it's 2 minutes from PIL home, 20 minutes walk into the nearest town (although that's turning into cafes and barbers only), reasonable bus route if I stop being able to drive, decent dog walks nearby.
Moving would increase mortgage by 150k - £200 more expensive per month than extending. Would have to be final move. I suspect we'd buy something new or nearly new because we don't want to have to do anything but decorate. It would be a different area because there is nothing in the immediate vicinity, but it would only be a 20 minute ish drive to PIL and we'd still be close to country walks for the dogs.
Currently in a 3 bed, to get the space we want we'd probably have to go up to a 4 bed, so council tax will go up but we live in a 70s build now so I suspect heating would be cheaper.
We've got the ok from building control for the extension (within permitted development) and we've started getting quotes which have been in the 100k region for extension, fitting kitchen and utility. Although we are still waiting for other quotes which could come in cheaper.
WWYD?
Ps Sorry its really long