and some of them have clung on to their party (& Brexshit) despite their constituency being pro-remain by quite a margin.

I live in one such. The outgoing MP was pro-remain!

Talk about complexity. All bets are off for a while.

When the blame game kicks-in, Brexshit will be the target. And no MP will be able to good-mouth it in any convincing way. They will lie, they always do. The public won't forget - well not within the 5 year tenancy.