Cheers guys.
NEV - I do have an app on my phone that came with all of the rest of the bloatware (OG - stuff you don't want, can't remove, but is there anyway ). I have a HTC Desire HD BTW I won't use the speedo app though as I can't be ar5ed. Most of my commute is country lanes and then I hit 3 miles of duel carriageway average speed cameras. They do however, face towards the traffic and no plate on the front of the bike
BWJ - just took the front wheel off and the sensor is as you mention, just a black plastic/Bakelite thing. All 4 lugs are fine but there is supposed to be a thin washer which I think is missing. I can't see anything wrong with it so I have reassembled it as I don't want to mess about due to the ride out tomorrow. It may now be working, it may not, but if it is not I will order the whole lot (10 days). The other bad design is that the cable is bolted tightly to the fork in 2 places so this may have broken an internal wire.
OG - It is an easy fix, just Bl00dy expensive. Cash from my TS fund, unfortunately. I will be updating that thread when I finish posting this.