service or mot or brakes

Hi All, My Cupra is due a service soon as I've owned it a year (2007 1p). I'm hoping to pick your brains to save some money (or tell me otherwise if you think it's not a good idea). I drive it less than 5,000 miles a year, mostly just a weekend toy. But it is remapped running a bit more power...

Just got my car serviced at Nationwide Autocentre and while the combined bill for the service (including 2 tyres, aircon service and a couple of other items) was not too bad at £414. I was some what shocked when they tried to convince me that both front and rear brakes discs were "badly"...