Where the RVR is not available, RVR values may be derived by converting the reported visibility. For different country regulations refer to OM-C.but..not for CAT 11/111.
The touchdown zone RVR shall always be controlling. If reported and relevant, the midpoint and stopend RVR shall also be controlling. The minimum RVR value for the midpoint shall be 125 m or the RVR required for the touchdown zone if less, and 75 m for the stopend. Refer to OMA for "Landing on Wet or Contaminated Runways".
In this context, ‘Relevant’ means that part of the runway used during the high-speed phase of the landing down to a speed of approximately 60 kt (GM1 CAT.OP.MPA.305(f)).
So, in a nutshell, if there are multiple RVR reporting systems, one can fail (AMC7 SPA.LVO.100)
If you are below 1000 ft when ATC advise the failure you can continue and if the required visual ref is obtained, land.
In General:
Any restriction to RVR and/or visibility will be shown by a limiting letter (R or V), meaning that any given value followed by a letter must not be converted.
R: measured RVR.
V: visibility which cannot be converted.
Values without a letter can be converted.
Reported VIS shall be taken 1:1 as RVR identical value (no conversion allowed) if limiting suffix “R” is shown.
In general, a conversion of MET visibility into RVR is not allowed for Cat 2/3 approaches, for take-off minima, or if RVR is reported already.
The sim question is all about knowing the regulations in principle and then using common sense to apply them in a practical manner.