Asbestos is going to be problematic. Fine if undisturbed but any renovation to the buildings is going to get very costly, very quickly.
A bit hazy now, but I seem to recall one issue at Linton was the electrical supply to the base and what the HO said they would need. In the order of 10-15 megawatts!
Cost to get the required level was prohibitive and estimated by the grid to be a 3 to 5 year timescale.
Another stopper was the isolated location was against HO own guidelines in that centres should be in urban environments where integration would be much easier and not overburden local resources etc.