Four pairs of the two cards issued by the Post Office (Pictue card series 8/81 but also referenced as WMPB SERIES 16 & 17).
Details of the four pairs are:
1 Mint unfranked and unmarked;
2 Shrewsbury post office postmark 26/10/81 on 14p Machin stamp. Unaddressed;
3 Shrewsbury TPO postmark 02/11/81. Unaddressed;
4 York TPO postmark 02/11/81. Unaddressed.