luv2andy, if you had been nicer from the outset and not made an arse of yourself, I'm pretty sure someone with knowledge may have come round your offering help in sorting it, probably for free too (or at least a cup of tea).
As above, there are dealers that are ok, and even so, if you are that worried about the car getting damaged, then just make a point of taking photos of the whole exterior/interior after dropping the car off, then they cannot argue should any damage appear, also take a pic of the speedometer, so you can tell whether they have taken the car for a spin or not. Do all this obviously infront of them so they see you doing it.