Contrarywise, with previous BMWs I've done the oil and filter, air filter, final drive oil myself, and asked the dealer to do bits that are a bit more complicated (brake fluid and, counter-intuitively, spark plugs on one bike). They were always happy to stamp the book. I've always changed brake pads myself.
Yes, the 1250GS and Arden BMW, Tunbridge Wells.
For the first time ever at Tunbridge Wells, the bike was taken through to workshop and was ready when they said it would be! The previous incarnation of the dealership (Coopers) were good on occasion but for services it was usually the case that when I returned to collect the bike at the time they said it would be ready, it was parked up outside to give the illusion that it was done. Then they'd say "Yes, we're just about to take it through now..." And if I went home or to work with the promise "We'll call you as soon as it's done" I would end up having to call them at 4:30 then have a mad dash to get there before they shut at 5:30! However, as I always had a free loan bike, it was an excuse to use it freely.
(I used Park Lane in London back in 2005 when I was working in London, as it was just a short trip on the tube to get to work from there. Called them mid afternoon to be told it was ready for collection. Got there at 5 to be told it was just being finished. Waited til 5:30 and was then asked to leave because they were closing the showroom. I asked where I should wait for my bike and they said I'd have to come back in the morning. Refused to give me a loan bike. Big argument followed but I genuinely think they would have locked me in the showroom for the night if I hadn't left! Needless to say, I never darkened their door again!)
If you're buying from Arden - or indeed any dealer - it might be worth arguing over the labour costs of the first service. But you just know that what you gain on the roundabouts you'll lose on the swings.
So all in all, Arden are doing OK by comparison.