Hi, Glen.
I can't claim any great expertise here (my main interest is in the screen-printed tumblers designed by AHW), but I have seen a fair smattering of Ravenhead advertising tumblers and pint glasses on e-bay. Mainly breweries and sporting events/ football teams. There are a couple of sets of "Gotta Lotta Bottle" tumblers on at the moment - not having a garden shed, I generally pass on advertising ware, but in this case I'm actually quite tempted as I've always been tickled by the "Gotta Lotta Glottal [stops]" slogan.
I've seen the Ravenhead mark on the base of pint mugs and advertising ware, but not on other tableware designs.
I think Frank's right that the value probably depends on interest in them as advertising history. I've noticed that milk bottles with screen-printed ads on them made by United Glass Bottle/ United Glass (Ravenhead's parent company) seem to get a lot of interest - whether that's from bottle freaks or milk fiends I'm not sure! Incidentally, United Glass are still going strong as part of the US Owens-Illinois group and still have a facility in Alloa in Scotland which will screen-print your bottles for you.
I'd love to see pics of both the milk and the political sets. Would you be prepared to contribute them (suitably credited, of course) to the Sherdley /Ravenhead site currently in gestation? It'd be nice to include a few examples of this side of Ravenhead's output.
Also - I'm intrigued by your reference to enamel-decorated carnival glass - I can't quite visualise it. Are there any pics on your site? I had a quick look, but couldn't see any - possibly because I got a bit distracted by the wonderful cartoon section...