For a secondary radar your talking a major infrastructure capital purchase or if they go for a feed an equipment upgrade and continuing payment every month for the feed ( tens of thousands per month).
The computer option apart from not being approved requires every aircraft to have a mode S transponder fitted. The problem traffic I suspect are not required or can't fit one.
I can actually see the problem from Southends point of view. They have a heap of traffic which they have to work or would like to work to get there revenue paying flights in. If the traffic doesn't speak to them it can make it almost impossible to get an IFR flight in with the required separation. They probably work there nuts off with GA traffic for no revenue gain.
If it does all come to a head and the CAA decides they need a secondary radar they will have to find a whole heap of cash for again no revenue increase in a time of decreasing traffic into regional airports. But you can guarantee that if they do have to get a secondary radar service the application for controlled airspace will be getting fired in.
I presume the controllers at Southend are like most airports in class G with CAT operating they pray for the days with the cloud base of 600ft and a viz of 900 meters.
They have now got to the point where there is a stand off between GA pilots not wanting to talk to them and not talking to them. And the need of the unit to speak to them to be able to function properly.
The MOR game is never going to work, SATCO's have tried it in the past, to much amusement of the pilots. After the initial shock of getting filed upon, after the first few which nothing ever happens about they just ignore them. Then daft competitions start with who has had the most filed on them. And god forbid the pilots start MOR's back, with a concerted effort you can shut the airport down through lack of controllers and have the SATCO knee deep in report writing and sick fed up of going to the tape library to pull tapes.
THIS IS DEFINITELY NOT THE WAY TO SOLVE THE PROBLEM BY EITHER PARTY.