Wanted: lower cost brake servo&master cylinder repair for Saab 9-3 London UK

Hi. I've just been told, by Saab City London, that my 9-3 Convertible needs a new brake servo and master cylinder. Saab City have always done a great job but the price they are quoting is pretty high (just under a £1000) and I was hoping there was an equally good repair place in the London area that wouldn't be so expensive.

Any recommendations gratefully received.

Thanks

James