Good Morning, Holdsworth tricycle conversion sets typically sell from £50.00 upwards. This price would get you a real shabby one for a reasonable one expect to pay around the £150.00 mark. Holdsworths have two types of drive shaft hub fixings.The stub axles or idler are all the same. Ken Rogers now holds all the spares for these axles. Don't listen to the horror stories about these axles if the stub axle is done up tight there will be no problems. You can even get these axles with hub brakes. F.W.Evans when Tom board was their frame builder built three tandem trikes with Holdsworth axles. These were modified by Frank Whitt S.V.C.C. He fitted self centring ball races to the outside of the axles and got Tom to braze or weld the axles directly to the hubs. Coincidently there is a copy of Tony Olivers excellent book "Touring Bikes" for sale on ebay this has very good advice on tricycles, tandem tricycles and tandems. It was on one of these Evans tandem tricycles that Tony stoked for Mick Butler on a touring holiday when they followed the Tour de France through the Alps! There is a mention of this in the book. The tales of there decents are legendary and anyone who knows these two can well imagine! If you have a conversion set running on 27" wheels and are not too happy with the handling try putting a 26" or 700c on as a front wheel this might help.
Oil up! Frank Ellingford London UK