Things I was told during my service from an independent garage is making me think my dealer has shafted me in the past.
Lol, I've been told by my main dealer that tyres/brake discs/pads have needed replacing when they've been at about 50-60% life left in them so I'd take most of what they say with a pinch of salt!
I can't comment on the main beams, but I've changed the sidelights in mine on a couple of occasions (tried LEDs but only the cheapo ebay ones which didn't work great!) - I'm sure if you can buy the right bulbs it would also be a DIY job.
It was quite fiddly the first time I did them, not sure I'd trust the spotty teen in my local Halfords to do it! If you're not confident doing it yourself, maybe get your independent garage to take a look for you...?