it is steadfastly remaining as a collection of twigs clinging tightly
to the brickwork.

Ours is going mad. South facing wall though.

green and sappy, not brown and dead.

Sounds like it's alive!

Incidentally it is growing out of largish pot on the patio, coult that
be it's problem?

Ours is growing out of a small wooden trough. It's kept well fed and
watered and does very well. Too well. I had to remove a load of growth that
had run through the guttering.

Al.