'Morning good egg,
It's a long time since I did ADC, (we had OKTAS then), but I'm certain OVC at 200ft would have triggered what we used to call 'LVP Cloud'. I can't remember offhand what procedures this condition involved, but if the procedures still exist, and they may be 'aerodrome-specific', I'm sure someone will be along shortly with the answer.
The use of the ATM, (Aerodrome Traffic Monitor, - a small radar in the VCR showing the traffic within, say, 20nm of the ARP), may have a part to play?
I can't find the references at the moment. Most of it was contained, (I think), in our airfield's MATS Part 2.