Right, just got back from a helpful VW dealer - hope my boss didn't mind my lunch hours... [:I]
He hooked the car up and fiddled with settings on the computer for ages. The car was set up for variable servicing, but the maximum value for miles travelled before the car flagging for service was set at 9300... In other words, the variable service program can be set up to show a service is required no matter what, between the ranges of 9300 and 20000 miles. It seems the variable servicing can be made less variable... [

!] He showed me a recent VW UK instruction which stated that the maximum 30000 mile service interval had been revised down to 20000 miles, following instructions from VW in Germany. [:O]
He had no idea why it was set at 9300 (they weren't the supplying dealer by the way) but stated that the onboard ECU hadn't shown anybody accessing it since it was built and shipped, so most likely the VW dealer in Leicester didn't do the PDI properly.
Anyhow, now all fixed, and the mileage to go before service now flashes up after startup for a few seconds without touching anything (like my TT used to) whereas before I had to push the trip reset button with just the ignition switched one click.
It's now showing 9700 miles to go before service required, which would amount to about 19000 miles before service which was much more like I was expecting.
The techie said that all of the memory in the ECU, eg miles driven, how hard and in what temp etc was all still there and would be part of the Long Life service calculations, hence I suppose the figure to go being 9700.
Incidentally, he's also setup the function which tells me the washer fluid is low, which wasn't set before!
All the above they did FOC by the way, so I suppose I should mention that they are Vindis VW (St Ives nr Huntingdon branch). They certainly listened to me and agreed that it was odd it required service so soon when they could have just fobbed me off and said it needed one anyway... Well done to them.