For anyone interested, the eBay seller I got mine from has more blankets in stock...
http://www.ebay.co.uk/itm/Olive-Gre...Collectables_Militaria_LE&hash=item460cbaca94
No association, etc. I should mention that I actually bought three blankets (one for this, two for the Daniel Boone challenge thing, or at least to try out as an alternative to a sleeping bag). Each blanket was different. They are all olive green, but from different makers, and in slightly different shades and sizes. With mine, the colour is pretty close on two, and one is a little paler. One of the darker ones and the pale one both weigh about 1.85kg, while the other darker one is more like 1.55kg. They are also slightly different sizes, and all are larger than the advertised size, except for one that has a length of 2.08m instead of 2.1m. Widths ranged from 1.37 to 1.42m instead of 1.3m.
From what I can tell, they seem to be Croatian, although google struggles to translate some of the words on the labels. The advert says they could do with being freshened up, and they could - they have that unmistakable aroma of natural fibres mixed with army surplus. The blankets are all in very good condition. I'll see if I can post some photos of the labels on the ones I got.
Oh - the seller was very good - very responsive to email, shipped really quickly, and gave a good reduction on postage cost for the multi-buy (10 quid in total for three blankets, compared to £6.50 for one).