Update: good and bad news on this issue with flash not working. Bad news is that I shot a roll of 36 exp Ilford B&W and it came out entirely blank. Only bit that had been exposed was the leader. It turned out the shutter was jammed.
Good news is that once I fixed the jammed shutter, the flash worked. The camera will only trigger the flash when the shutter is open, so once the shutter was ok the signal went to the flash shoe.
To fix the shutter I removed the lens and opened the back and gripped the shutter cloth from front and back with one hand, while pressing the shutter button. Jiggled the cloth a bit and it opened!
Can't believe it ended up being such a simple solution to a problem which looked complicated initially! Thanks for the input all.