It appears from my Google that LR orientated garages in “London” are no more, but LLR (link below) was I believe ok…. sometimes, they’ve been around since 1990 in Charlton but their web site appears to be down now, so may also be no more.
Anyway, assuming that your series has a petrol engine, like a 45 year car I own the fuel system is simples, petrol from the tank transferred to the the pump, in my case the pump is mechanical driven, then on to the Weber carburettor. So just the two items that could give me an issue, which I’ve never had.
So Im sure any local garage use to dealing with the older petrol vehicles would be helpful, and even with an oil burner if your series is one.
Let the Forum know how u get on OK.
https://london.cylex-uk.co.uk/company/lrr-range-rovers-13448091.html