For the R.A.F
Buccaneers instead of the TSR-2, thus money saved from not needing to design Tornado allows more F-4 Phantoms to be purchased., Short Belfast's instead of the C-130.
No money spent on developing Nimrod AEW, money spent instead on Boeing E-3 Sentry allowing RAF to purchase a full squadron of 12 instead of 7 which isn't enough for UK air defence needs.
All R.A.F.G & B.A.O.R bases closed in West Germany and the money saved allowing a doubling of the R.A.F so more able to keep US-U.K air bridge open in the event of WWIII.
British forces then would act as a Rapid Reaction Force. In the event of tension or possible war, British forces would scramble to forward bases in Europe similar to US Reforger Exercises.
The R.N
Navy halved in the 60's but with the savings, not 2 but 3 CVA-01 carriers would be built with a full air complement.
Also with the extra R.N savings a full fleet of SSBN's would be built with Polaris SLBM's, proberly around 12 or 16 for good measure.