Hi,
I am 99% sure I have these items, always pays to chuck these types of thing into the "Lucky dip" box of bolts when dismantling cars. These I am sure came of my old black VX Coupe.
They are 19mm head and nut, 75mm total length, 12mm diameter, threaded only at last 20mm. Kept the washers too. The nuts have a slot at the mid point. (If anyone can enlighten me to why thats done please do so - is it to stop over tightening?)
If you want them then just mail me your address and I'll pop them in the post.
BTW - I have looked at my Beta Coupe and they look like the ones fitted to my car.
Cheers
Matt