Could I

Put some French bean plants out now under some pop bottle cloches or is it still too cold

Yes you could and I'm sure they will do well unless we have a big frost, go for it.

My french beans are in pots and have been out for a few nights.  We haven't had a frost but its been cold. I've grouped the pots together, put sticks in  and thrown an old duvet over them.

You could put the bottle covers on then cover them with and old towel or curtain.

Eek! I've only just got the seeds out of the packet today...! I'm not too late, surely???

I shall be sowing French beans in succession up until early July, I just put a few in for the hopes of an early crop. 

The only reason I have planted out my borlotto beans is that I put them in too early and they are outgrowing their pots.  I saved my seeds from last year and quite frankly did not think they would grow so I put a lot in and I had over 90% germination  :happy:.  I have loads left to put in about the middle of June if I want a late crop.