There are normally two specialists recommended on here, but neither are down south:
1 - Chester Transmissions - as mentioned (in Chester, unsurprisingly!)
2 - Mackies, in Glasgow.
I've used both. Chester did the gearbox flush, which made the problem much worse (a common result, from other's posts on here, and not their fault).
I then drove it (VERY carefully…) to Glasgow, where Mackie's rebuilt it, perfectly - but expensively. I chose Mackies over Chester due principally to the quality of their guarantee - 100k miles on the rebuild
