Gary - Daystate quoted me £210 + carriage plus parts to service my Mk 3, it cost me £45 + parts to service my Mk 3 at my local RFD who is a Daystate accredited service agent!
John Bowkett is not really comparable as his blueprint tunes are not maintenance, they are improvements as well you should know (I have a Mk 3 S10 as well and it has been to Mr B). Independants were quoting £50-120 just to service the Super 10, so £120 for a Blueprint was not bad by any means!
I don't know how much John charges just to service, but remember a service from him will have all the latest blueprint modifications and upgrades done (the new hammer work makes it a lot quieter) so I would send the Super 10 to him for the treatment it deserves (and then keep it)...