Not car related in the slightest, but we are moving house so our bed which has been in storage for 18 months while we stayed elsewhere needs to be reassembled only to find that some of the bolts are missing!


It's a solid wood frame using 3" threaded studs with half moon spacers, washers and split washers, This is what they look like:

The head board and foot board have inserts threaded into the wood to take the studs and the side beams have circular cut outs for the nut and half moon spacer. The problem is they appear to be imperial (most likely 5/16") and 99% of suppliers in the UK can only supply M6 or M8!
We've driven to I don't know how many furniture and hardware stores and nobody has them. I ordered a replacement set online before realising the originals weren't M8, so they are no use. (Although the half moon spacers, wood dowels and washers fit...)
I've been scouring the internet today trying to find them but nobody seems to sell them. Although I'm reasonably sure that they are 5/16", and they need to be about 3" long, I don't know what thread pitch they are, whether they are BSF, UNF, UNC etc... I don't know much about imperial threads types unfortunately...
Can anyone help me find some or at least confirm 100% what thread I need ? At the moment we have a £500 bed that is only 5 years old that is just a pile of rubble on the floor, and SWMBO is not happy...

I now only need 8 studs and nuts - I've managed to piece together everything else I need.