I too am a Welshman. Hwyl!
The G Powershots are cool cameras. I think the main question is always "what type of photography interests you?" For mostly brightly lit outdoors stuff, the G12 will do brilliantly. The G12 will also fit in your pocket. And you will avoid falling into the apparently bottomless money pit that is DSLRs and detachable lenses.
However, I would heartily recommend moving to DSLR if you're really enthusiastic about photography.
I bought a 400D about four years ago and never looked back. My pictures taken on the IXUS Point & Shoot that I used before that just look horrible compared to the ones I took with the 400D (even though I really didn't have a clue on day one). I learnt loads with the 400D which eased me into understanding how to control the camera (the G cameras have great manual controls too, as I am sure you know). I then moved to a 40D and started building my lens collection. I now use a 5D MkII which almost always has an 85 F/1.2L II lens on it. This suits my personal taste for low light, intimate portraiture. It would be hopeless for sports or birds in flight.
I am very happy indeed with my kit. And while I think moving to DSLR is a great idea, once you start it can be hard to stop....