Chaps,
It's all down to experience and responsibility. Having spent 10 years in Engineering/Management prior to my flying career, the most I could have earned was around £40k. At the start of my engineering career I was on a wage that represented my youth and inexperience - around £18k in todays terms. I ended my Engineering days on around £40k as a relatively experienced Engineering Manager (Manufacturing).
After a substancial (un-aided) investment in flight training I was lucky enough to secure my first flying job on a DHC8-Q400. Now, this is where it becomes interesting. As a brand new FO on a modern Turbo Prop my starting salary was about £22k. To be honest I was happy with that as a starting salary as I was brand new, inexperienced and getting paid to fly.
The question is, does this wage refelect your experience and responsibility. Well, you could argue that a new FO earning £22k could have 78 peoples lives in his hands in the event of his Capt becoming incapacitated (It has happened folks on a DHC8-Q400 - MAN), on the other hand, you could argue that with such little experience why should they earn more????
It's very subjective. All I will say is, after several years of flying commercially myself and several thousand hours later I'm still earning less than I did as an Engineer (final years), but hopefully that will change soon.
As an Industry per se, our T&C's seem to be driven in a cyclic evolution dictated by supply and demand. At the moment there are too many pilots for the industry, so employers have reacted by offering less for new joiners. A sham maybe, but most airlines are heavily streamlined to maximise profits at the cost of you and me. When the good times return, hopefully things will improve.
To answer the original post, I think £25k for a brand new FO is good. Not ideal, nethertheless not bad, especially if you are 20 years old and your first job. If you are 30 years old and supporting a family, maybe you should have thought long and hard before jumping into this industry!!
Good luck to all
