How to convert recipes using US flour to UK-type flours

So many recipes on this blog and in many of my bread books use US-type flours, quite obviously,  But I am in England and baking using US recipes does not always seem to work well, probably due to the flour.  Does anyone know the equivalence between what is US All-purpose flour and our British flours, for example?   We have Bread Flour and Plain Flour.  I think our plain would be similar to US pastry.  But I think our Bread flour is lower in protein content than the US AP flour.  We also have Canadian Bread Flour, with higher protein content that our Bread Flour, but perhaps not as high as US High Gluten.  I am wondering whether there is a easy way to increase protein/gluten content of one flour to approximate that of another.

Even more confusing is Wholemeal/wholewheat; we have both 'normal' wholewheat and bread wholewheat flours.  Do the US recipes use the same wholemeal flour say for muffin (where we would use normal wholemeal) and also for bread-making?  

Anyone can throw some light on this confusing floury matter?    And, oes this protein content really, really matter?