More or less the same thing happened with mine, it was a fried movement. I think they tried to charge me a similar amount, so I argued that the repair cost was disproportionate to what I paid for the watch and they did a full service and replaced the movement for about £350. I'd give Andrew Michaels a call and see if he still has his ex-Breitling watchmaker; I think it is a relatively common ETA movement, so you could probably get a replacement for a lot less than Breitling will do it for you.
And yes, for all the naysayers, I'm sure there are loads of you that have old Casios/Timex/Seikos that are still running, but I also have several that aren't; the difference is you aren't going to bother asking a forum if your £10 F91W is fooked or not!