Hi Steve
There is a partial retest fee these days, all depends if it's taken away and or within a 10 day window.
Whilst they are not allowed to remove road wheels a visual inspection (light and mirror) can show the edge of pads on most cars, on a Focus its possible to see the end of the caliper and the pad end, it was clear (and totally fair it was my fault) that the pads were down to a very low limit (as in no metal touching but flipping close)......as she only does about 2,000 a year I had left the service way too long using my knee as an excuse but the truth is I messed up and they should have been changed 3,000 miles earlier. Dangerous to think that a 'just around town' car is OK and I know that lesson well as I have preached that enough times to customers so no one to blame but me.......Whoops. The old brakes worked perfectly at town traffic speeds but a few good stops at motorway speed would have had them fade away to nothing, not an excuse but just highlighting the dangers of how that can mask the real condition!