Early Disco remote fob

I have a 1992 Disco1 200TDI and am looking to replace the remote fob - the wife has lost the only one I had!!
A search on this forum only shows single or double button fobs. Mine had no buttons,. it was just a rectangular piece of plastic that had a red light that lit when the fob was squeezed. Remote locking gave up ages ago, but it was nice to be able to set the alarm with it.
I seem to remember reading somewhere that that type of fob used frequencies that are now illegal.
Does anyone have any suggestions where I go from here please?

D1 fobs have a button or two when it left the factory so perhaps you had an aftermarket membrane style fob, anyway have look for the alarm ecu it's behind and to the left of the glove box it will be black and have a tv style co-ax antenna plug pluged into it, so just make a note of the ecu part number and the frequency and search for a s/h one on e/bay and if your system & fob doesn't have any problems then you can program the fob to your ecu yourself, new fobs are available from Remotekey or a similar company.
The old frequencies with limited bandwdith are not illegal, they just can't accommodate all the modern stuff that's around.

Land Rover Discovery I Key Fob

don't know if it'll be any good as it says these cover 1993-1995 whereas your disco is a 1992.