Good question Fred and see why you 
'need' the Dunlop sign, fabulous. I would think that most collectors have a very varied 'wants' list. I suppose it depends on what you look for in a sign. Whether its the styllised script, multi colouring, detail, imaging, condition, or even the price of it, everyone has a unique slant of their 'ping' factor. For me the ideal composition is, manufacturers name, a product picture, a logo or statement followed by a price, well thats the spec I go out to look for. Not being a sign snob I am still a sucker for the industrial type sign when the wording is bold and striking.
I had a B P Winner, which along with others didnt do much for me , albeit we would all love the condition to be good as it could be, the Walter Wilson's shown is quite simply the best conditioned sign I've ever owned but it doesnt do that 'thing' for me. The sign that I own and still my top favourite is the Edwards, To answer your question Fred, and I heard that it was available, I would send 'her indoors' out on the streets again for the Imperial Manufacturers plate sign with the girls face at the top, or the Falkirks Enamel Company with the chimney stacks silhoette in the background. So good we're all different.