St. Eval
Yes they are initials. The ORBs list the crew for each of their ops exactly as
Sgt. Salvage A.J
P/O Searle R.N.
Sgt. Baker F.J.
Sgt. Hampson M.
Sgt. Davies I.G.
Sgt. Milliken D.W
The ORB's are very good quality so no problem in guessing the spelling - they did typo the initials sometimes but Searle was always with initials R.N.
Thanks for your help