<<UK ATC will inform pilots when the RVR is below the 'Absolute Minima' for a visual approach.>>
Where does that that appears in any documentation? So far as I can see the "Absolute Minima" procedure refers only to instrument approaches and does not mention visual approaches. Therefore, once an aircraft passes 1000ft if the measured RVR drops below his minima but he reports that he has the runway in sight and can continue visually ATC a) has no option but to approve and b) there is no procedure for filing a report.
(Not trying to be awkward but this is an interesting discussion).