My Bongo just passed its MOT with flying colours,

but had to have new front brake pads. It stops fine, always did, but now has a vibration at 65+ mph.

I had the front wheels balanced today which helped, but some of the problem remains as apparently the MOT place did not replace the spigot rings. I did go back there but they just looked puzzled.
How do I tell what size I need and where can I get them from in the South? Wheelquick is too far north for me.
I have 17" alloys in a granite finish. They came with the Bongo from Japan and are unmarked.

Never seen a similar set on any other Bongo.
If this matters at all, it is a V6 with LSD.
Thanks in advance
Terrier
The BewilderBeast - V6 Mean Green Tintop with LPG and 321 Away Montague Conversion