Just one other quick thing on the maker's mark....
 
Someone (I forget who now - sorry!) asked me in an off-list e-mail whether or not I had misread the second mark, the brown transfer print with the Staffordshire knot.  It was suggested that since this was incomplete, reading 'W.  [---]IAMS' in my interpretation, it might actually be a W. Adams mark matching mark no.30 on page 22 of Godden.
 
This was an entirely sensible suggestion, but the mark does not match the one in Godden - it's quite different in appearance (though the same site does, ironically, have a mark which is a precise match for mark no. 35 on the very same page).  It also seems clear to me that the letter before the final a is an 'I', not a 'D'. (and it's also worth acknowledging that as comprehensive and fantastically useful as it is, there are omissions in Godden, particularly with Welsh and Scottish manufacturers).  I'm not 100% sold on Williams for the second one, however (the first, blue, print is totally unambiguous), so will happily listen to counter-arguments.
 
For those of you asking for a photograph, alas the brown mark isn't from one of my sites.  However, photographs were being taken last week, so I'll see what I might be able to rummage up.
 
Thanks to everyone who offered help.
 
Alasdair