Hydrangea Petiolaris is a good looking plant when in flower. Can be slow to get going but a very attractive plant in the summer. Ideal for a big north facing wall.

I was thinking the same Inverglen, mine is on a fence in a shady court yard area and is very happy.

Climbing Hydrangea is also my first choice. There is an unusual purple flowering climber called Chocolate vine which does well in north facing locations as do creepers, but they are quite similar to ivy.

Thank you, I'd looked at a climbing hydrangea in the RHS guide I'd bought, but wasn't sure, it's really nice to have some feedback, there's too much choice. I think it will look great, I'll post some pictures next year. Thanks for the help folks.

Good choice. It might need a bit of support the first year or two but after that it will cling on by itself.

Indeed it will cling, but I also use blue tac above or below a stem to direct it where I want it to go so it fans out more.