Hi Paul, we've all been there, wondering if we've booked too soon and paid too much. My opinion is that it's always better to book in advance, if you were happy with the price at the time of booking, why worry if it's £100 cheaper 2 months down the road? The chances are that if you don't book and leave it a few months, it will probably be £200 dearer. Better to be safe than sorry
FWIW, £660 with Qatar from Manchester is par for the course. It's very rare you'll find anything from a regional airport for less than £600. I usually go from Brum with KLM or Emirates and expect to pay between £600 and £650. I flew with Qatar a few years ago, they were OK, Doha isn't the biggest airport in the world, but it's clean and modern.
There are cheaper deals from LHR with Saudi and others, but I've found out from recent experience that cheapest isn't always best.
