As it's a 30 year old part that;s not surprising! I guess the Irish contingent will havea mor elocal list of places to you, but places I know with buckets of spares are, in no particular order:
DA Marine (Newport on Tay)
MJ Marine (New Holland)
Boating Mania (Upminster)
And others that I can't remeber the names offhand :
one by the Canal to the East of Nottingham.
And off course good old Bill Higham in Manchester.
Google should find them all