Cranfield are apparently looking at installing their own radar within the next couple of years. They have objected to the siting of a new windfarm for that reason.
Again, who's going to pay for it? Like Oxford, Cranfield has insuffient commercial activity to pay for the purchase of equipment or instillation, let alone the ongoing running costs (inc. rated staff) without the owners dipping into their own reserves.
As for the windfarms, the technology now exists to eliminate the windfarms as unknown interference and become P.E.'s on the screen, it's expensive and helps if you have controlled airspace, but a number of airports (and, I believe the MOD), have done deals with windfarm operators to provide the equipment in exchange for dropping the objections.
A joint venture between Oxford and Cranfield to contract approach services out to NATS is probably the most commercially viable option.
If nothing else, in time, it eventually leads to only needing ADI ATCOs at each airport as the APP function would be done entirely by NATS.