This is a bit embarrassing as usually I'm the one identifying plants on here!
Anyway here it is - it's a twining climber, with ivy shaped leaves but it is not a clinging plant.
I had thought at first that it was wisteria because of the length of the new shoots and the apparent flower heads at the tips. However now the leaves have emerged and they are very shiny, dark green and look like ivy.
The thing is growing great guns and I think I will have to remove it wholesale as the client whose house it grows on thinks that it is the same monster that was taking over the wall when they bought the house. It has layered itself about a bit as well - joy!