Sent an email to technical support at Acewell on Sunday without much hope, but at lunchtime I had a reply (On a Sunday!) asking me to look for an undocumented (in the normal downloaded instructions) p prompt after the c for circumference, evidently p is used for the number of pulses before increment so if you had a 4:1 gearbox drive p=4 when I found p it was set 011 not 001( so my guess that indicated 4mph was 50mph was about right). Now of course its too wet to test it out, but I think that's it. Thanks for your suggestions and full marks to Acewell technical support, why cant big software firms be proactive like that instead of relying on FAQ by bystanders.