T-5R improvements

[KM2]

I finally got my 850 T-5R over to the UK this Tuesday. I had the headlights adjusted back home already so that does not need fixing. However I managed to pick up a tiny stone between the brakepad and disc on the rear left side - or so I think. If I drive really slowly it shows quite clearly and quick stops have not been able to dislodge it. At 25 or 30 mph the problem is not visible anymore but if it rubs against the disc at all times that is not exactly grand. Any advice where to get it fixed in the London area?

Additionally, been looking into fitting a LSD for some time. Any advice? Anyone who's got experience with such an installation?

Ta!

[KM2]

Actually a brand new brake pad seems to have disintegrated totally within 1200 miles of fairly normal driving. Within the next 100 (which I had no choice but do) it ruined the brake disc as well

Unfortunately wasn't able to find a volvo garage able to replace it on a Saturday afternoon. Any advice on where to take it?