We actually do make something for the Mini's
We have a grounding kit designed for the Cooper S. Although it is only one product, alot of our products are universal and can fit virtually any car.
The universal ones and the Cooper ones are similar, but the cooper specific wires are cut to the specific lengths to be grounded in the engine bay along with a custom created mounting bracket that fits nicely inside.
If anyone is interested, PM me and I'll give you a good price.