Jabba is closest, then Shark and R-Tech, but in 5 months I am moving to cornwall, have not checked if there is an R-tech or Shark dealer close by down there, I know that Jabba dont cover there (although to be fair the map on my 1.8T from Jabba was fit and forget, no issues in 5 years)
Shark might be the best as if something does go wrong there is always the chance they can post me an SPS to re-load maps, decisions, decisions.