Honda VT125 - I am 6'2" and 17stone and fitted on that quite easily. Will take some searching and travel as they are not that common, but worth the search.
http://www.ebay.co.uk/itm/Honda-shad...item4185e5d032
My other suggestion would be the Varedero (same engine at VT), can't find older one for lot less than £3000 ???
http://www.ebay.co.uk/itm/HONDA-VARA...item233edb4902
Both slightly higher than £1200 but a lot better build quality than usual 125 cheapness.
The V-twin engine has a lot more grunt than the usual 125 single, so worth going for if a slightly bigger chap. The other advantage is that they hold there money really well, so when trading in , you can get almost what you paid. My VT125 cost me £2300 and year later traded it for £2000, not bad £300 for a years riding!
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"You know, Scotland has its own martial arts. Yeah, it's called Fuk-U. It's mostly just head butting and then kicking people when they're on the ground"
The Stoppy King