as said the en-ratings are generally considered a bit conservative ... i think i read somewhere that when mammut adopted their ratings their bag returns due to temp issues fell drastically, take that as you will
WM ratings can usually be found with some creative searching as european review and retail sites often list the en-rating
i personally wouldnt buy a non en-rated bag unless it was heavily discounted and even then id take the "rating" with a grain of salt
when you consider that THN, MH, marmot, REI, SD, Kelty etc ... all en-rate their bags, theres no excuse for a more mainstream manufacturer not to ...
as to cottage ... you get what you order, they are smaller shops ... thats the risk you take
its quite weird that BPL which is usually pretty scientific endorses use of loft rather than the generally accepted rating system used by many manufacturers both in the US and euroland ...