I recall a similar procedure during my time at RAF Linton in the mid '70s. If the JP pilots wanted radar monitoring after depature (usually in poor weather) then the request was abbreviated to "C/S request take-off and climb". Tower would inform the Linton Zone Controller, and then transmit "C/S clear take-off, call rolling on Stud 5". The pilot then lined up on the runway, changed to Stud 5, and transmitted "C/S Rolling". It saved the pilots from having to change frequency when just airborne and entering IMC. Tower would also monitor Stud 5.