Might as well use the expertise that exists out there with the specialist restorers - Historic Flying rebuilt the BBMF's Hurricane after it's disastrous force landing and subsequent fire, and you couldn't fault their work. It ain't worth the mountain of logistics and admin required for the RAF to do one aircraft every so often; used to be OK when it was done on a "grace and favour" basis, but as you say, the accountants run it now, and if HM government doesn't get value for money, then vintage aircraft will be removed from RAF service as a cost-cutting measure - I don't think that any of us would wish to see that.