Hi Abu
Welcome to the Forum
A BMW Dealer will have an hourly rate close to £200 (someone has to pay for the free coffee) plus Oils, Filters and Fluids
Try a search of the Register of BMW Specialists there should be one nears you who will (a) have all the right kit to provide a good full service and register it on your iDrive.
(b) They will also have up to date Diagnostics but hourly rate will be probably less than £100 per hour, no offense to Halfords Kwik Fit or Mr Clutch but I wouldn't let them loose on my BMW I have watched Kwik Fit boys slamming wheel nuts up with a windy gun and then put a torque wrench on the wheel nut!!! Yep it clicked, it would it's vastly over tightened.
Hope this helps Good luck
Dave