Who is your dealer? Do you trust them?
To me that is more important, I use a garage for my car that is part of a national chain, it is not cheap. However my Brother in law is the assistant manager so if they say it needs something, it needs it, and if they say they have done something, it HAS been done. If you trust the dealer then carry on if not, find some one you do. I know cost has a bearing on it but I would rather pay and have faith in my motor than skimp and have a breakdown at sea...
Just my 2p worth.
I agree with Andy though, do as much as you can yourself as long as you are confident to do so. There are plenty of local ribbers on here that are probably willing to help, that includes me if I can.