Ohlins servicing

[cheeky_chops]

I have some Lotus spec, two way with remote dampers, covered 34000 miles in 4 years. Just taken them off my VXR220 as one of the fronts is leaking.

Looking for some advise on servicing? Can any bike shop with the kit do it?

Also should i get all 4 done or just the front 2. I was told £120 each a few yeas ago so £240 saved is useful as i also have a 4th year service + cambelt to pay for!

cheers P