lol you've done your homework well i see
either way, both (SEALS and SAS, as well as SFOD D and SBS) are special forces units and their members can all be expected to be more than sufficient at (unarmed) self-defense... wether a person can still apply the techniques at age 70 depends on the person himself, and probably to a certain extent the techniques (although i suppose all techniques used by special forces will be pretty intuitive and straightforward), but wether he's SAS or any other unit won't matter