Chris, service intervals are every 4500 miles for your bike, alternating from a minor to a major service. So assuming your bike has a full service history it should have had it's first 600 mile service, followed by a 4500 minor service, a 9000 major service including valve clearance check and now due a minor service. Due to the age of the bike it may well be your interest to have a full major service carried out including oils, filters, plugs, coolant change, brake/clutch fluids, brakes, throttle body Co2 check and adjust and a valve clearance check. The valve clearance check is done on a stone cold engine so make sure this is done correctly and ask for the clearances.
Costs are about £140 for a minor service and £350 for a major service.