Gatwick has RETILS (3-2-1 countdown lights) installed on 08R/26L RET's to help keep occupancy times down. Not sure how effective they are in LVPs. As for runway capacity on a busy mixed mode runway in LVPs, ATC need to ensure arrival spacing is sufficient to ensure that ILS integrity is maintained for consecutive arrivals and for departures between arrivals so if it cannot be guaranteed that arrivals will achieve the desired exit then until ILS is replaced I can't see any benefits for runway capacity as arrival spacing will remain unchanged. The only benefit perhaps is giving a slightly earlier landing/take-off clearance to the following aircraft.