RH23, ex-Summerhill, was converted to a tree lopper in 2002 to replace the last remaining Van Hool Atlantean with Dublin Bus, D635. It is used to cut low hanging branches off trees so as they don't damage double deckers buses.
Above: RH23 in Broadstone Yard on 7 July 2003. Note how it still retains the ad frames either side of where the destination scrolls used to be. It was the only Olympian to have this feature
Below: RH23 in Broadstone on 4 August 2003