Bluntly, there's no mileage for the UK in any active involvement in or support for either side in what is squaring up to be a very bloody sectarian war. The choice is between supporting Hezbollah and the mad Mullahs of Iran, or Al Quada and the insane Imams of Pakistan. This is a Shi'ite / Sunni war, not a proxy for East vs. West or communism vs. capitalism. This is Islam eating itself, and the harsh reality is that every Jihadist from either side who succeeds in killing themselves in Syria is one less that we have to worry about.
The press may be concerned about the several hundred Pakistani youths reported to have left the UK to fight for the rebels. They shouldn't be. Those few that aren't killed by Assad's forces should be arrested, convicted and imprisoned if they try to return to the UK - either way, they're out of action.
As in the Iran / Iraq war, the two sides will only have the will to stop fighting once a certain level of blood has been spilled; we're nowhere near that point yet in Syria. Both sides still believe victory is possible and are negotiating for weapons, not peace. The best thing we can do is stand back and let them get on with it until they're both exhausted, then step in with the reconstruction contracts.