We also had this appliance (and its sister ERH 176L) occasionally be sent to us at Scunthorpe as spare pumps - I remember driving it one day on a freshly resurfaced but undulating road in town - I heard an unusual noise on the roof - turned to the oic to say 'I'm going to pull up because I think there's something loose on the roof' and noticed the 45'ladder laid neatly on the road behind us - needless to say we stopped, picked it up and put it back on the ladder gantrys ! - it turned out the action of the smooth road and gentle bumps had caused the head release gear to lift (weak spring) and allow the ladder to roll off !!!!
Added by Rick Loudon on 13 November 2011.