I heard back from Paul Brodie this morning:
"Hi Shamus,
2503 is an 18" Exspresso, completed June 12, 1993. There is no note of who it was sold to. We often sold frames only, so I cannot say if it was spec'd with a Gatorblade.
All the best,
Paul"
So there you have it! I have also asked if the 1993 Brodies were spec'ed with rigid forks (ie Gatorblades), though I believe they were, then suspension forks for 1994(?).
I haven't had much time to work on the bike yet, only the bottom bracket has been installed.