Another quick gear question...problem...

I got my crash damaged sv about 3-4 weeks ago. At the time it would slip into neutral no problem and snick into 1st. The bike needed a lhs rearset but I used it (stuck in 2nd gear) to go to the shops 2 or 3 times. Nothing major, not over 30mph and it's less than 1.5 miles.

Now I have a replacement rearset and:

I can't find neutral and when I do think I've got it, it won't flash up the neutral light. This is in false neutral and it will eventually 'slip' into gear!

I'm 'missing' a gear. Can't tell if it's 1st or 6th gear though. I do know that in what I think is first, it will redline just shy of 60mph, but taking off it seems awfully....chuggy. So it 'could' be stuck in 2nd gear. In what I think is top gear, it will be doing 70mph at ~5400 revs. It will not, in any circumstances with any amount of force find the 'missing' gear.

Can anyone throw up any suggestions? I haven't even touched anything really!

i take it the bike had been down on the left side

so could be damaged selector forks