If you have the red warning light on and brake wear symbol for one of the rear axles ,yet nothing could be found wrong ,can you still drive the vehicle 
I would say so but keep a copy of the mechanics report with you .
I’ll stand to be corrected…but i’m pretty sure you cannot drive with a red warning light. I.e it would be a test fail and would also leave the vehicle with a stop notice if checked. If the red warning light is not correct, i.e there is nothing wrong then the garage.fitter or whatever should disable it. And record what they’ve done.