"I have a pack of Letraset Centra British bird transfers. I have a poster somewhere which I am sure came with the pack. They would have been bought probably around the late 1970s for my 2 children. We only used one pack and have just come across this in our attic."
Unfortunately, shortly after this contact, we lost touch (although of course I'd be very glad to hear from you again, Carol)!
The photo below came from a much earlier contact; part of a very large lot (1678 trade cards!) which the seller was unwilling to break up. Consequently, all I was able to salvage was permission to use the photos…
So there's just enough evidence to establish that these transfers existed — but that's it. The only thing I can add is that Centra were started in Ireland in 1960 as a chain of franchised convenience stores; they're still going strong.
Thanks to Adrian Allen, we now have a decent scan of one sheet:
Picture Credit: The SPLAT Scan Archives — Adrian Allen
© Tom Vinelott 2020