I don't recall any shortage of 301 series engines, certainly in the late delieveries at Coningsby. We used unrestricted power and we knew the difference.
We were the wing earmarked for the Far East deployment solely because we had the bigger, more powerful, engines. Later, when Waddington took over the role all the jets were swapped over too.
In Cyprus we made do with the 201 engines.
The 301 had a larger diameter and a short tail cone. This was a great benefit as the jet pipe could be slide out to get at the fire tec boxes. The smaller 201 series required the tail cone to be removed first.