Mike, a lot depends on flight times and the airport you wish to fly from. In my opinion sub £200 is a very good price. If you are outside school holidays (which September is) there are normally some good prices around as flights are plentiful. I much prefer to pay a bit more now for better flight times, this flying in the middle of the night malarky is too much hastle. I have previously booked many flights around Christmas as I have found the prices good as the agents realise everyone is skint.
Good luck