Take the other side main stand bolt out and us a M8 stud or a smaller than 10mm bar that will go all the way through and tap it out from the other side, the M10 bolt has corroded with the centre stand inner bush. You’re not the first to have this problem. When you put the new bolt in use some anti corrosion compound i.e. copper ease or some grease.Tried to fit mine today but the main stand bolt just refuses to come out, it's un-done from the bracket but is just spinning in the stand... Help! I am a bit buggered now as it won't do up or come out.
If the bushes are rotten, give us a shout as I had some marine grade stainless ones made up for people without a centre stand. Same size just won’t rust.