I have realised something regarding the 4 on ebay.
http://www.ebay.co.uk/itm/Sinclair-C5-Never-used-and-still-sealed-original-packaging-/110843929398?pt=UK_Collectables_Bicycle_RL&hash=item19ced02336
The last production ones had NO BOX's. But were in fact bubble wrapped as there were no box's left. This was clarified by A Harper, who was selling bubble wrapped C5's ( he had 14 left at the time I spoke to him ), and also read an article that stated this also and on the final line of the C5 that the last were sold from site at £50 ea. So how can the last 5 have box's ?