It does take a fair while for them to get growing and make roots to cling to a wall. However they do eventually.
Actually we have a free standing one as the supporting wall was removed a few years back. Seems happy enough.

Welcome to GoY Suze. They do grow slowly, and are very good at supporting themselves, so yours should be fine.

When this happened with my father in law's young one we stuck the branches to the fence with strips of sticky tape until it started to cling by itself. (Looked a bit odd because the tape was red...)