Thanks - I sent an email to Mike Ellis just now.
And thanks to everyone else for the replies.
So far I've been able to find out that:
The Signia Marquis were made from about 1997 until about 2002.
The shell is 6mm/5ply North American Maple with no support rings. Marquis have die-cast hoops.
The normal Signias were 5mm/5ply maple with support rings and triple flanged hoops.
Both types used the same lugs,snare strainers and holders.
They were made in the Premier factory in Leicester, England.
I've been told that the factory may not have kept records of the serial numbers so it is of no use for anything other than identifying the drum if it was stolen. This hasn't been confirmed yet.