http://www.igmaynard.co.uk/bongo/forum/ ... =1&t=25825
They are used to hold various items of trim to the bodywork, including:
Front wings - for securing the inner wheelarch protectors
Rear bumper - for securing small plastic panels to the bottom of the wheelarch & also the mud flaps
Under the bonnet - for securing the heater air duct to the front slam panel

Having originally bought some from a Mazda dealer for just under £2 each, I have since discovered they can be bought in bulk for a fraction of the cost. There has been quite a bit of interest in these, so I have ordered several hundred pieces such that the savings can passed on. I can supply them at the price I paid which is 21p each plus postage & packing of £1.50 regardless of quantity ordered. Please drop me a pm with your name, address & quantity required. Payment can be made by cheque or Paypal. Alternatively, I will bring some along to any meetings that we attend.
Please note: I have only been able to get these in black. There are two different sizes used on the Bongo, but these ones can be used to replace either type.