Think the board in Uddingston Seat said around 80-90 for first service, and i think ~120-140 for 2nd service.
You could phone them and ask them the rough price, they have a board with all models + prices on it (closest SEAT dealer if your in Edinburgh like myself - its about 30 mins along the motorway and turn left as you get to Showcase cinema, then down the road, turn right at the roundabout, first left, then first right.)
well not quite directions after mutlimapping it, it feels like that though ( http://www.multimap.com/maps/?hloc=GB|G71%206BS )
Number is 01698 817137
Think your other option is Arnold Clarke, but i think you would want it done properly.
Alas i bought my car just after it's first service so i can't tell you the price i'm afraid.