Bolt sizes to afix spare tyre carrier to 2nd gen?

[asgawth]

I have the standard spare tyre carrier on the back of my 2nd gen Surf. The sort that's fixed onto the back corner with several bolts and swings out to allow access to the tailgate. Noticed the other day that some of the bolts are missing. Don't really fancy the idea of it coming loose...

Does anyone know the correct size (thread, diameter and length) for these bolts?