Jacko Page (para and SAS) commanded an armoured squadron (RSDG) in Gulf War 1.I seem to recall that until the sixties(?), the Parachute Regiment didn't accept officers directly. All DE officers had to transfer in from other regiments, or in Phil Neame's case, another service.
Edit. H Jones' biography by John Wilsey gives the idea that all subalterns of a given era were encouraged if not expected to have an attachment elsewhere, be it Parachute Regiment, SAS or AAC. H chose the Paras whilst a contemporary of his, Paddy King-Fretts passed SAS selection, both going on to command units in their chosen worlds. It seems YOs of the fifties and sixties were afforded vastly more latitude in their early career. Notwithstanding the the fact that the army was about four times the size it is now.