Just don't tell anyone you want to join the SF 'Big Four'; Para, RM, SAS and RAF Regt
Daughter was a member of one of the big four
. Actually what they did, which was training to operate in the porous friendly rear areas, certainly had elements of SF. Indeed they were given training by 21 SAS.
When on exercise in the States the Reservists they were working with could not get their heads around the Regiment role and thought of them as SF. They certainly could not understand the authority weilded by an SAC.
Also on one exercise in UK they cleared out an unmanned but otherwise active SAS hide much to the embarassment of the SAS.