2006 Vauxhall Meriva passenger electric window intermittently not working - electric burning smell?

I've had this fault pretty much since I purchased the car 18 months ago - I think it was probably there when the garage sold me the car but they have passed the buck and told me that my warranty doesn't cover electric window faults.

The window intermittently stops working - its got to the point where I just won't use it anymore and have taped off the buttons because it was jamming with the window midway open - sometimes it would work again after an hour if I let it be but the last time it stopped my window was open for 2 days!! Not reaaally very practical. There always seems to be an acrid stench of (what smells like to me) electrical burning which orignates from under the bonnet and usually fills up the whole car. I'm taking an educated guess that this isn't just con-incidence.

My regular garage didn't even want to speculate and recommended that I go find and specialist in vuaxhall electrics. I can take it to Vauxhall and get the thing scanned but I resent paying 80-odd-pounds just for a diagnostic if its something I can try sorting myself.

Annnnnnny suggestions appreciated :)