My dad joined the British Navy, in May 1943. On his service records, the first entry is hard to read, but the first word is Royal, and then Batt (or maybe Batl) and possible 'u' and 'a' at the end? He is listed as Prov. Mech Group III. I am wondering if this is an enlistment centre, or initial training camp. He was there for just over 11 days before moving to signal school. He enlisted in Portsmouth, so I wonder if it is something to do with the Royal Naval College?