I finally located a towbar through Watling Engineers Tel no 01727873661. It cost, including the ball about £260. The firm were very easy, patient and helpful to deal with on the phone and delivery was very quick. The chap who fitted it for me said it was well made. It is detachable, though you have to undo two bolts to take the bar off. Watling do not do a quick release detachable. Hope this information helps others. I also bought a transmission oil cooler from Kenlowe for £110.00, just to be safe!