Re: Flying Instructor or Airline Pilot????
Why not both?
As far as I know, the best way to build hours today is still flight instruction. If you take your IR and ATPL's now you save the CPL written exams.
When you get your FI licence, and especially if you get your ME FI license, you will become more attractive to the airliners. I don't know how things look in the UK by now, but in the US you can 'easily' get at least an airliner interview with say 400 hours multi out of 1200 TT.
And for the record, I believe you will need an instrument rating do to any kind of flight instruction.
Cheers