Jfazzer, Srilankan is a great airline. Their service is warm and excellent. I have flown on their A340s and their A330s and in each, all classes have PTV's in all seats. Their catering is excellent and they have improved their punctuality out if sight. You are bound to have great flight with them.
The airport is safe as it can be. There is currently now a ceasefire (since Jan of ths year) so things are really quiet there now. This has seen large number of tourists coming to SriLanka (especially Germans) So do not even worry on that repsect.
Srilanakn operates 9 flights per week between Colombo and London with A340-300 aircraft. Only the Wednesday and Friday departures from London go via Male (UL 502) , the rest is all direct. Need any more info? Then go their website... http://www.srilankan.lk
Are you staying in Colombo? If so for how long? Being a regular visitor to Sri Lanka, I can give you some tips on sightseeing. If that is the case, just send me an email and I will be more than happy to help you out. Hope you find all this useful.