I am so glad I started this thread even if it has wandered off in a slightly different direction, ie. optilaps and re-framing etc!
thank you all for you tips and advice (I'm quite comfortable to be seen as some kind of nutter if it means I can get what I need! LOL)
My original post was loosely based on a few reviews saying vastly over-priced polaroids are often no better or even not as good as so-called cheaper pairs!
I wanted ideas on how to check if a nice cheap pair would be value for money, I had absolutely no idea that the colour of the lens might determine the suitability for the use of the glasses (thanks Stealph Viper!) Again I discover that what I stupidly imagined was something simple, turned out to be far more complex. It appears polaroid is a similar term to hoover, and covers huge variations!
Perhaps I should have asked if anyone has a recommendation for an inexpensive, but effective for general fishing purposes, pair of polaroid glasses