In response to the noticeboard article of the St Paul's 2s6d Gold Omitted a Circle member recently contacted me and sent images of six new examples, one owned by the member and the other five by a friend. The five examples owned by his friend included a corner marginal block of four:

This now takes the known mint examples up to eleven.. still a very rare stamp.

Full noticeboard article can be read here :
Noticeboard Item 3