Might we see an up-close image of the stamp(s), and of the opposite if it's marked as well?
There's a little history on Pipedia that has made me somewhat curious as to the date of the pipe's manufacture. Do you know if yours is an original production, or one of the 2006 stummels? I say "original" with some hesitation as I don't know how much is known about the period of their manufacture in relation to the company's history, but it would be very interesting information.
"In the late 1990's the last Mr. Huybrecht retired and passed away a few years later. He left over a 100 bowls. Many were unstained and without stems. In June of 2006 we located the old bowls and are now having them stained and stemmed. The mouthpieces are hand cut Vulcanite and every pipe is stamped "London Castle, G. Huybrecht". [Pipedia]
That is an interesting point.
The small business operated 1919-1999 , according to my source production seized with the passing of the last mr. Huybrechts in 1999 .
Alledgedly he exclusively supplied only one retailer, being G.F. Smith and Sons snuff shop 74 Charing Cross Soho. But according to Jensen he also supplied Astleys.
( The shop closed 2011 after a rapid decline following the retirement of its proprietor Vivian Rose, reports say that after his retirement the new staff was hard work and prices exuberant. )
Smith's snuff shop offered the stummels and then the customer decided what stem he/she preffered.
The stummel then was stained and fitted with a handmade stem.
Apparently Maxim Engel , pipes2smoke , also offered a limited number of pipes from mr. Huybrecht's legacy,
fitted with pipes2smoke made stems.
Pipedia also agrees he worked for Barling ( ! ) and carved stummels for FrederickTrant .
I suppose the stummels were not 2006, only finished in that year.
It seems impossible to exactly date my pipe, though I'd really like to know.
Could be old production, unsmoked, could be a GH stummel finished by pipes2smoke, or MB.