[Arran]

You really need to make a trip out to one of the regional swap meets, that is where you find junker sets and parts chassis with what you need. In my experience ebay is largely a waste of time for trying to buy a parts set, too many people can't seem to tell a junker apart from a viable restoration project if it's still in it's cabinet. I lucked out last fall with a RCA parts chassis for my C.G.E model E-81, it was a chassis from a parted out seven tube RCA console model that not many are looking for. You may have better luck searching for a chassis rather then a whole set, small sets tend to bring higher then average prices on fleabay in the same way that consoles bring lower then average prices.
Regards
Arran