Hi Everyone,
I believe I may have solved the mystery and answered my original question. I now have copies of Rex King-Clark's books. In 'Forward From Kohina' there is a reference to MILSON. The author writes on page 33; "2 Platoon (Milson) is now in Saye....", on page 40; "Milson comes back to A Coy from Saye tomorrow", on page 41; "Milson came in to see me in evening. Milson has some fine tales to tell about Saye. I am going to have a talk with 2 Platoon tomorrow".
In 'The Battle For Kohina' Rex King-Clark on page 33 gives a list of A Coy staff including platoon officers. For 2 Platoon it shows Lieutenant J B Teale. However, in 'Forward From Kohina' on page 23 the author writes "31st January Johnny Teale has gone as 2 I/C to 'A'....."
I conclude, therefore, that Lt Teale was promoted to 2 I/C of A Coy leaving a vacancy for platoon officer of 2 Platoon. Milson (presumably Lt) clearly reports to Rex King-Clarke and is with 2 Platoon which suggests he is the platoon officer.
Hence I conclude from the photo of my father and other soldiers with the sign of 'Milson's Marauders' is that of some of 2 platoon soldiers, part of A Coy, taken sometime after 31st January 1945 in Burma or perhaps later in India on exercise preparing for amphibious landings on Malaya (later cancelled). Consequently my father would have been at the Battle of Kohina.
Thanks for all the pointers in the right direction, it is very much appreciated.
Greg C