The first troops of this Commando formed up in several locations. ‘A’ Troop in Gamblingay under Capt. Wylie R.E. while the H.Q. Staff came together in Billericay Essex. A small party of ‘B’ Troop formed in St. Albans and the remainder in Newmarket under Capt G March Phillips who was later to command No.62 Commando.
After this scattered beginning all the various sections came together finally in Felixstowe at the end of July 1940. H.Q. being in a school in Station Rd Felixstowe.

Under a restructuring that only lasted a few months No.7 was combined with No.4 Commando as the 3rd Special Service Bn., under the command of Lt. Col. Dudley Lister MC before being redesignated again as No.7 Commando. Lt Col F.B. Colvin took over command from Lt Col Lister MC who assumed command of No.4 Commando.  
December 1940 the Commando embarked on the ships ‘Glenroy’ and ‘Glengyle’ for passage to Inverary where they underwent boat training.
31 January 1941 the Commando embarked for the Middle East, arriving at Alexandria as ‘A’ Battalion of ‘Layforce’ .