Well I did read what Jeppesen has to say about it and didn't quite fully understand it. Which is exactly why I posted my question here. Sadly, I'm not working with you on a long haul flight which is why I'm trying to learn off here. Thanks for your advice in any case.
Jeppesen states that - "RVR visibility values are charted only when the value is not the same as the prevailing or meteorological visibility value. When a difference occurs, the respective RVR and prevailing or meteorological values are prefixed with 'RVR' and 'VIS'. When there is no difference, the minimum is shown only once and means either RVR (if RVR is reported for that runway) or visibility if measured otherwise."