While maintenace was the resaon for scraping the Vulcan display flight, it was the crippling cost of a major for an individual aircraft at, IIRC, £1m that sealed its fate.
I was also an increasing diversion of resources at Waddo as the E3 was working up. Had it not been grounded when it was it would have been grounded a few years ago as main bases close and base loading increases.
There is propably no room at Coningsby so there would be no question of a single flight base.