For correctness, Keith Newton did NOT restore the first sandcast in the Uk in '85. The bike he restored, UK registration YLY70H was a die cast engined bike, being famous in the UK for being the bike used by the UK motorcycle press in various magazine road tests of the day. Keith was certainly one of the first to restore a CB750 in the UK, although that "honour" may actually belong to a guy called Eric Warburton who restored another early UK die cast, AYU 972H which feaures in Pete Shoemarks book "CB750 Super profile" (published in 1983, so definitely pre-dates Keith Newtons restoration).
Back in the mid '80's here in the UK, the existence of sandcasts was generally not known, no production sandcasts ever being officially imported into the UK in '69.
As an aside, I understand that Keith Newton actually owned one of the original late pre-production CB750's in the mid '80's and did deal to SWAP it for the die cast engined UK road test bike YLY70H, the restoration of which he then carried out and completed in 1985.
Cheers - Chris R.