The modern RAF is more risk averse than a primary school road safety lesson; there is no way on earth anyone would want to sign off on yet another bodged-up update of a knackered old airframe nowadays.
Well would you, Stopstart? It isn't the age of these airframes per se that is the problem, it is the lack of an audit trail spanning that age. The "bodging" was done well before the various updates (proposed and/or abandoned). It was done when certain VSO's decided that well established engineering custom and practise was no longer needed. They ordered the regulations to be subverted, that those engineers who wouldn't comply be got rid of, that they be replaced with unqualified yes-men and -women, and finally threw out the regs so that they couldn't be quoted back at them (or so they hoped). Unairworthiness crept like a canker into the military airfleets thereafter, fatal airworthiness related accidents ensued, all finally leading to Haddon-Cave. All that led to was a hamstrung MAA that had only one option, to ground those fleets ASAP (or those that seemed the most compromised, which generally meant the oldest ones). What goes around comes around...