The front row are all marked 'MFA' which I assume is Medieval Field Artillery, with - from the left - a number; 2, 4, 7 and 5 (A gardener-gun...of sorts!!!). All are also multi-part ( well, at least two part!) kit construction.
Also any luck on the Panits Lazlo info. John?
Closer inspection of the adjustable bombard thing suggests a faint '74' on one of them, if that helps?