Probably the most unreliable car I've ever driven

Hi All... am new ... just registered...
I am having some major probs with my 2003 A4 Avant 1.9TDi. Over the last 18 months it intermitantly doesn't start first turn of the key, sometimes it takes 3 or 4 attempts to start - upto about 30 seconds. Having driven diesels for 12 years now it seems like it could have been the glow plugs. It's been in and out of Hitchin Audi for this five or six times, they say they can't replicate the fault, they have even had it for 3 or 4 days on occasion and always give me the patronising question 'do you wait for the yellow light to go out'. My last car was 1.9TDi Golf which in the 3 year I owned the car always started first turn of the key.

Last week the brake warning light came up on the computer panel, took it in to Hitchin again they changed some cables saying it was a problem with the sensors charging me £146. This week the light is back on, so have booked the car in again for Weds.

Despite the problems I still think the car is great, and really enjoy driving it, however the aftercare is just making me think I wouldn't buy another Audi!

I was wondering are these common faults on the car, has anyone else experienced them if so any ideas on a solution....

Cheers

Stan

Cold starting; have they mentioned the water temp sensor? These go duff and fool the ecu into thinking the engine is warm when it isn't.

Flashing coil light; usually caused by a faulty brake pedal light switch, about £10-15 and an easy diy fix.