I would be very surprised if Akrotiri plays any significant role in a theoretical combat operation against Syria, for the very reason that it is so open to attack by TBM and the huge complications that direct involvement in local hostilities would bring to the UK-Cyprus relationship. The US have plenty of bases of their own in the region (e.g. Souda Bay and Sigonella) which are outside TBM range but easily inside the combat radius (with AAR) of all likely participating aircraft. The UK could easily base its forces elsewhere in the region, as seen during the Libyan operations.