Lets get some facts straight shall we?
The owners of Oxford cannot justify the costs of an approach radar service by installing their own radar, based upon present commercial income at the airport, unless they want to do so from their own resources. We are talking of an investment of £1m plus just to get it installed and flight checked, then you've got ongoing costs of ATCOs and engineers. Anyone who questions costs of less than £800k for a 0600 -2000 operation has no idea of the real world.
There is some justification for providing a joint approach radar service for Oxford/Cranfield by one unit, but where is the funding for this going to come from?
LARS? Oh dear! you've got to have the ability to provide the basic services before you even get this far!
Radar at Oxford is a laudable idea, but it's got to be commercially viable.
The only way a long term plan would work is biting the bullet and contracting out to NATS, the current "Odd Job" way of doing things there is simply not a viable idea.