Hello
I am currently cataloging a newly purchased stock of British Stamps from George V. I am quite an experienced collector from this period but have come across a very strange watermark on one of the 1d Red stamps from the 1912-24 era. The stamp appears to have the normal Simple Cypher (w100-Stanley Gibbons)but it is on the far left of the stamp when viewed from the back. On the far right appears to be a different watermark similar in appearance to the "Garter" marks on Queen Victoria stamps. I have never ever seen such a thing before. Anyone got any ideas or comments on this? I would be grateful to hear from anyone who can explain this.

