I've been flying the 109 offline for about the past year. I won't profess to be an expert but I'm good enough mostly to defeat the AI in one to one dog fights and I can hit ground targets proficiently enough.
I haven't played much online because I haven't had time for that much until very recently. I also think that for good ping, I'd be better off only playing with players also based in the UK like me - which limits the pool.
However if you are UK and you'd like someone to play with or against (I fly the spitfire too). I'd welcome that - it's about time I started flying with real players in any case. AI only takes you so far.