My Tipo 1.4 T-Jet is booked in for the 18,000 mile service at Pewsham Garages in Chippenham and they quoted me in the region of £300. As it will have only done 5000 miles since the last service I asked if I could just have a Low Mileage service (basically an oil & filter change) instead, which is costing £170 plus VAT.
I'd say £456 is taking the mickey really, particularly as the Southampton branch has a variable reputation. I know its not great in that part of the World for dealers since Westover went, but if you can deal with the drive I'd recommend trying either Monza Sports Tuning in Ashington (Sussex), who are likely to work out cheaper even witn the extra fuel cost and have a brilliant reputation for Fiat & Alfa Aftersales, or alternatively try the new Fiat Dealer in Salisbury called August Motors. No idea what they're like but they're already a Honda Dealer and I can't imagine Honda giving a franchise to any tin pot outfit.