dashboard noise

[finny]

ive got a really noisy creaking rattle coming from between the screen and dash board about 3" to the right of where the drivers side tweeter hole, ive tried stripping bits off, jamming various bits of wood/rubber/metal in anywhere around the area I can put them, ive tried spraying wd40 and silicone spray, ive had a mechanic lay across the dash trying to find the noise whilst driving, has anyone had anything similar? and found a cure, its driving me mad, the best way to describe the noise would be like a large blob of rain hitting the screen, it happens more as you drop off a bump in the road or whilst reversing off my drive but in a way that the van would be flexing. im thinking next having the screen taken out incase its that or with it removed maybe seeing the problem. this really is the last straw with this van, so many niggly faults, my mk1 version im sure was built better. if I cant sort it im going to trade it in on something else