07 Tiger 1050 Starter Motor

Hi all, Broke down at the end of summer in Bristol with starter motor issues. I really sounded like a horrible grinding cog grating loud noise.
Got rescued back home and have taken it to a local garage. They have just quoted me £2000 to fix the starter motor. Including new chain and sprocket.
The mechanic said Triumph have put a new version of a starter motor on this model and it cost £500 but also needs an adaptor plate which costs £600.
I must admit I panicked a bit as the bikes got 39500 miles on the clock and i bought it with no service History as it looked like it'd been so well looked after. But i think it's market value would only be £2700 max.
I love this bike, it was a dream come true when i found one i could afford, i had some brilliant touring holidays on it with no issues at all.
The mechanic offered me £750 for the bike which would mean I'm going to be saving up for a hell of a long time to buy another bike again, esp with redundancy at my work looming.
I put it on market place for £1500 yesterday and have two guys really interested but also loads of people said I could get a starter motor for £250 on Ebay! And have it fitted for £100. Loads of guys say i should also ask on this forum for help. Really confused about it all. I've worked on loads of old 2 strokes 50ccs etc in the past and have looked at anything on you tube for help but only found this video on the sprag clutch fix.
Looks like quite an easy fix to me if it is this problem. although the guy on the video says when a sprag clutch goes it makes a tick tick tick noise whereas mine sound like crunching gears. How much are the parts and has anyone here done one?
Any advice at all would be appreciated greatly.

 

I gave up on the end and sold it for spares or repair.
Extremely fed up with triumph for not doing the decent thing and doing a recall on this problem.
It was the gear on the starter motor that had stripped. The garage was quite correct in saying that the repairs could be over 2k as triumph no longer make the starter gear this size anymore. So if you buy the upgraded starter then you need to buy the new cog it connects to, then this of doesn't fit in the engine casing!!??
Thanks Triumph, you have lost out as I'll never touch another Triumph motorbike again and will definitely look for another manufacturer to purchase a new bike from.