Okay so got the new part the drive cog with lugs on it fitted it and the speedo worked parked the bike as it was a bit of a crap morning and when it got nicer took her out for a spin only to find the speedo was working on and off.
So I parked the bike up and stripped it all down again the drive cog was fine and the speedo sensor with wire coming out looked okay,the speedo was working fine so I think the speedo pick up buggered as when I put it all back together it wasn't moving the speedo at all I thinking its going to have to be a new speedo sensor which brand new is 98 quid
can't find any secondhand,I did give deefer a message so will wait on a reply to see if he can halp out any.
Just not had alot of luck so far with this bike and I'm already on a tight budget as I took on a loan to buy the bike in the first place just a nightmare lol.
Just thought I'd update the post and let you guy's that replied know what was happening.