Interesting to see that the BBC and Daily Telegraph both have articles today asking this question, albeit with different headlines:

1) The BBC:
Are UK bombs making a difference in Syria?
Later rather pointedly:
It is of course still early days. But given the limited number of UK air strikes it begs the questions: why was the government so keen to expand the air strikes to Syria, and why the agonising over a vote that appears to have changed relatively little?
Link:http://www.bbc.com/news/uk-35166971

2) DTelegraph:
RAF bomb raids in Syria dismissed as 'non-event'
Since MPs voted for war over Syria RAF Tornados and Typhoons have mounted only three strike missions
Later citing a regional SME, Jon Lake:
Britain’s air campaign in Syria so far is basically a non-event which can have had little, if any, impact on the balance of power on the ground.
Perhaps the RAF has a far better role to play, the MoD says so:
The Ministry of Defence said that the RAF’s contribution to reconnaissance over Syria is more significant, with some reports that it is providing up to 60 per cent of the coalition’s entire tactical reconnaissance capability. It declined to specify the number of reconnaissance missions flown, however.
Having merged in a thread which asked 'Can the UK-US still work together' to this main UK defence thread, it is a coincidence the question is being asked again.