Bouganvillea.

I wish we could grow these in the UK.

You can grow the Purple species. I've seen photos of them grown outdoors in the UK. Maybe covered in coldest biting weather...but the purple will cover in bloom by mid summer or so.

I don't know of any which would survive a winter here Stan.

You might try Bougainvillea spectabilis also called brasilensis. Or close.
Its the hardy purple,more likely to survive in London..or for sure the milder areas like Cornwall.

You might have to get ingenious in very cold weather,to protect them.