Crikey - you guys are paying a lot for tyres.
Get on to wheelhouse tyres in Brum or Busters in Swansea.
Also try Sherlocks (devon)
Last time I bought off-road type tyres for the beemer, it cost 115 for a PAIR for TCK's
You should not be paying much more than 60-70 quid for a tyre.
I'm now running 17" front and back on mine, and pay less than 90 quid A PAIR (unfitted)! for Dunlop D207's but these are really road biased....
Unless you fancy spending lots of money - do a bit of shopping around dealers are not the best value.
If you are capable, take the wheels off, rather than the whole bike.
My local dirt bike shop charges 25 quid per wheel fitting on the bike!
(But only do this if you know what you are doing....)
I rather take the wheels off myself, as I know what I have done, and I take a lot of care.
Re:- servicing, you can keep costs down by taking your own oil, plugs, filters etc in - BMW can charge silly amounts per litre! But the oil must be the right grade, ditto the plugs and filter(s)
Also - don't be afraid to ask for a breakdown of costs to justify a seemingly high service cost.
These bikes are not complex machines - they are relatively simple, so for servicing out of warranty, your local bike mechanic should be able to cope with it with ease.
I know I might come across as a bit - errm - Tight with the money, and anti-dealerships but after seeing the mechanic at clarkes checking the starter wiring on my 1150GS, and shorting the battery several times, I vowed never ever to go clarkes again unless desperate.
Anyway - that's my two pennies....