Thanks for the advice guys. I did try with a pick and tweezers but it proved too tricky due to the fact I couldcouldn't see in the hole and have tools in there simultaneously (due to the fact the hole is at a right angle to where I can get my eyeline, I could only see in the hole with my phone camera).
In the end I went a bought a set of magnetic screwdrivers (which I didn't own, this is my first attempt at servicing a vehicle, I'm new to this), and managed to get it out. Panic is now over.
Thanks again :)