Well I've always used MS, but recently I've found that Parkgate over in East Belfast is cheaper by far. I got a couple of quotes for a 48K service recently and MS quoted £178.98 inc. VAT, Parkgate quoted £110.00 inc. VAT. I've bought cars from MS and always found them honest and good to deal with. My only experience of Parkgate was recently when I took a friend there to buy a Punto. Again they provided a decent service and threw in free mats, a 12k service, etc. They're trying to build up business as they're a new dealer, so try them for a quote. I hope that helps.
Fiat Brava 1.6 HSX, Fiat Uno 1.1 ieS.