Cool, make sure they put the correct oil in, not sure about the later models but the early ZF transmission is very fussy and many transmission 'experts' think it is ok to put generic fluid in which it most definitely is not, as long as they are a RR shop you should be fine.
Not sure on the towbar, I bought my westfalia bar and electronic kit, which is the OEM fit for my year, from PF Jones and fitted it myself with the 13 pin connector, they may know someone in your area
https://www.pfjones.co.uk/