Today, 11:04 AM
There's not really anybody that actually fixes these gearboxes in the UK, although some gearbox specialists may be able to do so.
If you can get hold of a second hand autobox, then that could be the way to go. What year is yours? Even with a matched gearbox ECU, early PFL cars aren't entirely compatible with some later boxes. They'll work, just not quite correctly.
Manual conversion is obviously an option too, but again depends on availability of all the necessary bits, but it's a...