Hi Baz,
I had a small stainless steel mounting bracket (about 3 mm thick, 200 mm long, and 12 mm high with 2 threaded holes at each end to line up with the licence plate holes) welded onto the underside of the lower bar of the oval front bumper that essentially positions a slim-line licence plate in front of the
oil cooler.
The licence plate is mounted onto the mounting bracket with 2 "Allen-head" screws.
This works just fine for me for street use and if I want to do some track work, the plate is very easily removed to maximise air flow.
Regards.....Paul