GB - Qe2 With Bars On Face - Training Stamps

I am familiar with the issued tagged with graphite lines on the reverse of the stamp. These stamps, found in a lot purchase, appear to be quite different.

First of all, they have very wide black lines (graphite????) prominent on the face of the stamp. It is wider than the back tagged stamps and is of an uneven quality, not appearing to be uniform in application. From this small sample, it also appears to be rather irregular in its centering with several showing distinct shifts.

This sample appears to be all unused though only two have gum on the reverse.

Can someone please tell me what the markings are. Are they some form of experimental tagging or just some individual playing games? If they were legitimate trials, when were they made and how many stamps of the issue were so tagged? Were any actually used in the Post or were they sort of "in house" trials?

It's an interesting looking issue - but only if they're real.

They look to be training school stamps.

See this post - https://goscf.com/t/12823

They are indeed.
There are thick bars, thin bars, horizontal bars, different space widths, one bar, etc etc.
Also worded overprints like 'School Specimen'.
A fascinating area of GB Philately.

Londonbus1

Thanks for the ID and the link. All I need is to have another interesting area to keep an eye on!

I have retitled the thread to possibly make your response easier to find.