I agree, it could be a dodgy sensor.
If you do get the red warning light, the ABS unit will be bricked!!!
It will cost thousands of £'s to replace!
HOWEVER, the good news is that there are companies that can rese tthe unit at a fraction of the cost (still hundreds of £'s and you need a mechanic to remove the part so you can send it off).
Please see one of my posts earlier in the thread for one such company that offers this service (I have no affiliation)