Here is an update. I have a new buyer for the bungalow who is very keen and seems as secure as one might hope - but as I know things can all go horribly wrong!
I have been to see the alternative new build and it is lovely - ideal for my needs with wonderful views, that are almost the same as the view we had from the cottage that we lived in for decades before we had to make the move to the bungalow. It is a view that has my heart.
It is possible that, because the whole group of houses might not be complete before March 31st (when my buyer here wants to be in to save the stamp duty), I could move in and rent the new place whilst awaiting completion. I would get stung for stamp duty, but not as much as I might as this new place is cheaper. The builder is going to make sure that mine is finished first. Swings and roundabouts.
Fingers crossed - surely it will all go right this time - please!