Hi McWho,
I'm where you probably want to be in about 6 years i.e. in my fifth year with a large UK airline. I was on a 'tagged' airline scheme and trained at a well-known UK flight school. I was liable for the course costs. Not being rich I had to take out a large loan.
I was fortunate and got offered the job straight out of training and didn't pay for the type rating. I see, on average over the year, around £4k hit my bank account each month i.e. I am not destitute by any measure. My only debt is the flying-related one - about £1k a month (there's still about 4-5 years left of repayment). I rent a small 1-bed with my girlfriend in the south-east as we both work out of London airports (I see you're in the north but remember that while following the work you might be paying substantially more in living costs). We don't live particularly extravagantly.
The problem is we are still really struggling to save a deposit and get a mortgage for a family starter home in the south-east. Despite me being in the top 5% of earners in the UK. The big issue is the HUGE unsecured outstanding debt, relative to most other people. Out credit ratings are fine.
My point is that I made an informed decision to go down this path a few years ago. I weighed up the risk/benefit and did it. It's worked out for me and I don't really regret it BUT I had no REAL idea, 6-7 years ago, what such large loan repayments meant and how drastcially they affect your life, especially if you have any plans to do the normal stuff that comes with a successful career - find a partner, drive a decent car (mine's a 10-year old battered Audi), buy a house, have kids, etc. These things seemed very distant when I was going through selection...
We'll get there eventually with the house but a lot more saving/thrift will come first. It can be tough some times. I'm not complaining, I'm a HELL of a lot better off than most, especially in the current climate, but it's important that you make peace with yourself over these things now if you think they may be important/relevant later.
Good luck in whatever you decide.