I've used World Air Fares several times for cheap BA tickets. No issues.
They are quite responsive to email too in case of re scheduled flights etc. Was getting responses within 2-3 hours.
Only issue was on an AF booking and AF point blank refused to re route me after a cancellation. WAF wanted to cancel my flight and refund me minus £50 fee. I refused.
Ended up getting them to send me a final refusal from AF to re route me and booked my own re route. Sued AF via MCOL for my re routing costs and they settled in full.