Thanks for everyone's replies. I admit a small mistake.... After I posted this I had a quick look again at my library and pulled out my 'Polygon Yak-1' book. It had hastily been described to me as the 'Yak 1' book as my Russian and Cyrillic know-how is a little limited. Thakfully by wife is Russian and she normally sets me straight on these matters.
Closer examination proved that this book was the "Pervyi Yak" book I was after. This left me quite pleased although a little embarrased that I posted this without checking more closely. You live and learn. Sorry about that.
I obtained the book on EBay through the Seller I mentioned earlier. I will go through the links you chaps have mentioned in my continued quest for "Yak-9: Ryadovye nebes"..... Many thanks everyone.
By the way - we do have one very good retailer in the UK - check out
www.aviation-bookshop.com