Me again guys, just had a look at the reprom, there’s no mention of not pushing back the Caliper pistons , in fact they even described doing so with their special tool. So I imagine there’s been a problem in the past with debris getting back flushed into the ABS unit, bleeding the system seems pretty normal .
Before I change the pads I’ll flush out the system with new fluid to minimise any dirt ingress.
We had the problem on the wife’s car, series 1, another common problem. Brake fluid is hygroscopic and the moisture that gets into the fluid rusts up the valves in the ABS distribution block, for a while they repaired it as a goodwill gesture, when that finished they discounted the valve block by 60%, we missed that boat too and had to pay £600
Regards. Mick