I believe Simon to be correct regarding the Anniversary Wheels being No Longer Available.
An alternative wheel choice may be Minilite alloys, maybe? Williams have a 4/4 up for sale with centre lock Minilites on. They'd give you prices and availability on them, I'm sure.
I have a set of 4 anniversary wheels for sale and the cream 4/4 at williams has bolt on minilites, (i put them on)