Yes correct you can only continue past the OM/1000 AAL If the report Vis/RVR is above the minima, Nothing to do with cloud. And i do not work for Manx2 i work as a professional pilot and live on the island so im not sure about what CAT the manx2 was (lets not speculate now).
As far as number of approaches goes I've never heard of any rules about number of approaches that can be made in sequence or respective weather rules for this. As far as i am aware you just need the vis as detailed above and sufficent fuel for the approach a missed approach and divert plus the normal final reserve then there no limit on approaches.
But we dont know what happened and as said before we should learn from facts instead of blame on speculation.