Not strictly correct that the car needs servicing every 2 years.
Here's the extract from a 2003 manual (the age of car your talking about)
It just has to have the oil changed and under separate section the brake fluid is a 2 year time based change.
While conventional systems rely on distance
traveled alone to determine when a
service is due, the BMW Maintenance System
has taken the actual conditions under
which the vehicle is operated into consideration
for years, because miles can be
traveled in many different ways:
From a maintenance point of view,
62,000 miles / 100,000 km accumulated in
short-distance urban driving are not the
equivalent of the same distance covered at
moderate speeds in long-distance highway
travel.
The BMW Maintenance System includes
the Engine Oil Service and Inspections I
and II.
Determining the maintenance intervals
based on the actual loads on the vehicle
covers every kind of operating situation.
Minimal use drivers, who drive fewer than
6,200 miles / 10,000 km per year, should
nevertheless have the oil changed at least
every 2 years since engine oil deteriorates
over time, regardless of use.
While I change my oil every 7,500 miles or annually whichever is the sooner I woudl not worry unduly about a low milage car that missed a time based oil change. It's not like driving it huge distances on old oil.
I do echo the sentiment of a11y and personally I don't like ultra low mileage older cars. They can spell trouble. I was once offered a 15 year old Escort that had done 1,600 miles from new. Old boy drove it to the village shop every couple of day and had never been on a single journey of more than a few miles. It still had plastic on the rear seats but needed a new engine/rebore and the tyres etc. were rotton.