Its gone there was only an hour or so left when i posted.
I still can't help thinking that a rebuild is the way to go. Its all labour and as some of the other forums you've been on have said (copy and paste is handy eh) maybe a couple of hundred in parts. Labour rates to yourself are very competitive, even if it takes 3 times as long as a garage.
Speaking from whoppingly expensive experience with 2 dud v8 engines in my old landy both proposing to be great and costing the best part of 500 apiece. Second hand, even apparently rebuilt WITH RECEIPTS is worthless.
Do you want to be back here again in 6 - 12 months. You have said its your ONLY transport, my landy was at the time i lost 2 days of work fixing it. With some planning a little research and a couple of days off if need be you can have a bike you can depend on. You have a tidy 8 year old bike, i have one at nearly 30 and the 'new' one is chasing 23 and has a BAAAAAD reputation for turining its guts to shrapnel at the drop of a hat.
The cat is a very solid reliable bike and if some idiot had ridden it properly you would be laughing but they didn't. So you have a problem that wants a solution.
Forgive me being very direct here but you can either throw out several hundred quid and be no better off, except spending the time swapping the motor out. Or you could step up and fix the bloody thing. One thing for certain its not going to get better and the bits of junk that come off that gear are going to be causing lots of wear in the presently good stuff. And having experienced a siezed box i reccomend a prompt decision.