Just wanted to confirm your initial deductions were absolutely 100% correct. This was a Testron SF2CE Accelerator pt2 setup.
I've since wiped and burned the ST2HF roms and now have a great running CPS1 board awaiting the Darksoft Multi.
Only other weird thing was I had to re-burn the sound roms (18 and 19). Was probably a bad burn on the 19 as certain voices like countries and dying sounds were not coming out. Fixed now!