The recommended interval for the inspection service is every 12 months or 10k miles (15000 km) - whichever comes first. The list below is the minimum you should expect from your local franchised dealership or specialist workshop -

• Engine oil changed and oil filter renewed
• All components that influence emissions visually checked
• Exhaust system checked for leaks or damage
• Engine checked visually for any leaks or damge
• Concentration of anti-freeze content in coolant checked and topped up if necessary
• Hydraulic fluid level checked
• Fault memory interrogated for all systems
• Ignition timing, lambda operation, idle speed and CO content checked
• Brake system checked visually for leaks or damage
• Thickness of brake pads and discs checked
• Gearbox, differentials and CV joints checked visually for leaks or damage
• Suspension & steering joints checked for play, leaks or damage
• Tread depth, wear pattern and pressures checked on all tyres
• Door hinges and lock cylinders lubricated
• Operation of door locks checked
• Operation of ALL lighting, warning lamps and horn checked
• Windscreen wiper blades checked for wear or damage
• Operation of windscreen wiper & washer system checked
• Road test :)

Something that the service book fails to mention is another little known maintenance point on the universal joint of the propellor shaft (connecting the centre and rear differentials). I managed to dig out a few words on this from the service manual for the UR and Sport quattro. This is to be done at the annual inspection service. Photos to come soon hopefully...

• Clean the lubricating nipple on the propellor shaft - it may be obscured by shielding.

• Lubricate the propeller shaft with a multi-purpose, lithium based grease

Other items worthwhile checking on an annual basis are as follows

• Condition of the hydraulic pressure regulator (bomb) checked
• Air filter checked - cleaned or replaced as necessary
• Bonnet & Tailgate locks lubricated
  
• Condition of turbocharger and intercooler hoses checked visually
• Boost pressure test
  
• Both radiators checked visually for leaks or damage
• Operation of trip computer checked
• Condition of V-belts checked visually and replaced if necessary
• Check hydraulic clutch for leaks or damage
• Operation of ABS checked
• Condition of suspension bushes, wheel bearings and mountings checked
  
• Operation of air conditioning system (if fitted)