Daveo I think I have this problem too!!
When I picked up the Ceffy.. I was like WTF! Water on Wolf 3D ECU! Not good lol.. Have had it under cover since so have'nt had to deal with it again.. May be in troubles next time I'm driving in the rain though. Maybe a fault with seals, dunno?
I think AgentR31 is onto something.. the guy that installed the Wolf is apparently dodgy, wouldn't be surprised if there was no gromet. Also my inner plastic guards are gone due to scraping