A mill file would work, although I’d tend to use a double cut flat file. Cambering is also possible using an extra coarse diamond stone if you have one. An 8″ radius isn’t too much metal removal across a 2″ iron, as it works out in the region of 1/32″ of metal to remove at either side of the iron and arcing to zero at the mid point/centre.
A quick double check using dividers or compass on paper should confirm this and you can create a template – if desired – and superglue this to the blade being ground. The template can be removed using acetone once you’ve obtained the desired radius. 😉
Thanks guys, @kevinking, Its a friend of a friend sorta deal and no its not busted. Living in the same city where Veritas HQ is has benefits as sometimes these deals do pop up occaisionally. Just have to keep an eye open.