Bit out the way but APT near Norwich, family run and has a history of dealing with RS cars (although now focused on jap stuff), Scole Engineering owned and run by brothers (used to be linked to the RS Owners meet held near Diss but that is going back a few years when it was split between Scole and Weston Longville) or Clive Atthowe, Norwich (years and years of tuning) - appreciate these are all in Norfolk but none would let you down....good luck!