Hi Paul, thanks for the url, and to Emmi for commenting. Nice site! I'll definitely use it when I'm tempted to call something Whitefriars. If Whitefriars made as many pieces of glass as are sold under that name on ebay then they would never have gone out of business.
I'll keep looking for the maker and report back if I find anything. It appears well made and although the construction is not so different from the smaller Ravenhead vases that come up regularly, it appears to be of a different texture, and has a weight and quality about it that suggests it might be worth pursuing.