320 p,
the respective Minima go together with your landing capability:
Cat3 Single will allow you a Min of 50ft/ 200m RVR (-->CAT3a airfield Installation)
Cat3 dual will allow you a Min of 15 or "NO" and 125 m RVR (-->Cat3b airfield)
Loss of Cat below 1000ft Ra ( triple click) will in any case lead to a go-around unless you have visual clues to continue or it has happened below alert height (=200ft-->inhibited)
Should be clear as mud now...

PUH