Hi 172_driver & Lord Spandex Masher,
Please see this map of LGW.
http://www.ead.eurocontrol.int/eadba...2013-07-25.pdf
Low ViS Ops Procedures:
"1.3.3. DEPARTURE
1.3.3.1. RWY 08R
Entry via CAT III holding point at H3, J3, J4 or J7."
We are not replacing RVR readings for take-offs in 125 m visibility, we are confirming that the required visibility has been met using 30m spacing lights at the start of the take off roll, and verifying A 90 m visual segment is available from the cockpit at the start of the take-off run. All the RWCL lights are 15m apart after the landing threshold where the Touch down, mid point and stop end RVRs have been measured.
According to your logic, are we and ATC all wasting our time entering RW08 via J during low vis ops?