Same as the ones I had @j4ckal absolutely crap. Cheers for any help you can offer.Yeh they are just rubber well nuts. The ones that came on my vanstyle ones (same as oem I assume) pulled out too easy. The bolts are only small dia. something like m4 or m5.
I think I may of binned them, I'll have a look in garage and will measure them if I didn't