Hi Staurt, I had a feeling I might be slapped with an over stay, I did mention this to boarder control in Suvarnabhumi when leaving but they didn't seem to have a clue! I was told that cause it's a BOI work permit I only need to leave on the day stated but if it's a normal work permit I'd have to go down the route of cancelling the Non - B visa, but after reading up online it seems that this applies to BOI also. I wouldn't normally be bothered but I'd be looking to apply for a permit again once I return, so the last thing I want is any hiccups down the road.
Yeah I'm not sure if the embassy will help but it's always worth a try I suppose :)