Try STA they have an office in Manchester, I use them regularly and find them very competitive, in the past three years I've paid as little as £310 and no more than £625 the cheap flight was with KLM and the other two flights were with Qatar, if your dates are flexible you stand a better chance of a decent price. You will find STA on the internet and then you will be able to access your local branch tel No and address. Good Luck!