1956 Thin Flan Thruppence, not Gurnsey

[DrP]

Hi there, my friend asked me to check out his 1956 3d coin that has a really thin flan. I looked this up but could only find the thin flan 3d from Gurnsey from 1956. His coin is not the Guernsey one but looks like the normal 1956 3d brass coin but with a thin flan. Anyone seen this coin before?   

Maybe I didn't search hard enough But all I could find reference to was the Gurnsey variety.

Thanks in advance for any information.

DrP