Hi Peter,

Thanks for the reply.  In your first picture, fifth try square down, 
looks a lot like the ones in my post:

http://billwebber.galootcentral.com/1805-013.JPG

Two of those four are marked:

I.V. Hill
Grays Inn Rd.
N. Kings Cross

I guess that pattern wasn't unique to anyone?

I like the user made wooden try square you posted.  Easy enough to build 
if the local grown wood is stable enough to plane flat and stay that way.

best regards,

Bill W.
Nottingham, PA
Woodworkers visit me at http://billwebber.galootcentral.com/