Fourtrak Cab Spray

[PandaMonium]

All right, troops?

Just joined the site, hoping to pick a few brains and maybe benefit from those more experienced. I don't own a 4x4 but I'm pretty much constantly underneath my mate Fourtrak since I have the spanners and a history of wrecks I kept on the road, and he isn't too experienced with home mechanics.
He's got a problem in his cab with water spraying up into the passenger side. Seems to be localised around the end of the dashboard and heater vent, and the windscreen at that corner. We haven't had the dash off yet (too many more important jobs to attend to at the moment, but I'm positive we'll get to it).

Was wondering if anyone has experienced a similar thing, if it's common to Fourtrak's (or if not common at least known), and what might be causing it.
My guess is big bloody holes in the bulkhead but we cant find any from the engine bay. It has a snorkel but it doesn't look like it's the culprit either.

Also while I'm here, does anybody know of a decent replacement for the glow plug relay? Daihatsu want £178 and Toyota want £266. When I stopped laughing I told them I think that's too much.
Any suggestions (other than scrap it)?