Update thanks to a new prrt from Jerry Auton all seems sorted. Now the puzzle - original prrt purchased from motor factors having asked for the 82 deg stat but was given an 88 but they couldn't get an 82. so purchased an 82 oem from Rimmer Bro which was fitted but I had the above problem with.. Jerry ordered one off eBay which is now fitted however it's black but has 78 stamped on the stat inside - outcome is engine warms up, bottom of rad and hose get hot, rad fan starts at 94 as shown on live events on emerald software, temp drops to 89 and fan stops - 3 cycles and all looks fine - road test tomorrow. didnt think you could get a 78 prrt - but all is good