Have been in there to have a chat, we looked through the software and I was told there were three identical grommets on the firewall, so I ordered a couple. They turned out to be a couple of small rubber stickers (completely wrong).

Not sure if 34361fc000 is correct, that looks like a rubber ring/washer? The original was a blanking plug basically, which I'd like to try to find again. Thanks though!

The hole in the firewall enters the cabin behind the pedals if that also helps, was used to run vac lines and senders for gauges.

Might go in again to see if they can get anywhere further with a VIN.