Thought I'd just update the thread.

I've now had the trigger worked on by the local gunsmith and well, its a different rifle! She is now brilliant. Best £20 I've spent in ages.

He had to replace the trigger spring, the factory one was "very heavy" in his words.

The trigger pull is now approx 14oz: She will not fire with a 12oz weight but will with 1lb weight.

Andy