Player's Cigarette cards from England were so overproduced, that your cards are likely authentic and cheap because they are so plentiful. Reprint British cards will usually have an overprinted back; most of the reprinted sets are about golf, or actors. But the feel, smell, size, edges, stock, and glossiness of the cards can all be tells.
The links at the bottom will help you determine authenticity of cards.
http://www.net54baseball.com/forum/c...ivecenter.html