Landships II

Hi,

I was looking into finally starting a Takom 21cm Mörser, and while comparing it to photographs I noticed that in most cases, an extension seems to be mounted to the rear spade (hope this is the right term). It appears to be a drilled, rectangular plate, as can be seen on some pictures on Landships II:

Does someone here know more about this detail? How was it fastened to the spade? What were its dimensions? Are there pictures showing more details of it?

I'd like to add it to the standard kit, so any help is much appreciated!

Best regards,

Thorsten