The snapper told CarAdvice that he believes the car to be an Astra GSi, and not an OPC, by the badging on the car's gearshift. Unfortunately he was knocked to the ground by the "crazy" test driver before he had a chance to hit the shutter.
He also told us the rev counter showed it was a diesel.
Compared to the standard diesel variant the GSi also appears to have a revised from bumper and larger twin exhaust outlets. It is tipped the even hotter OPC variant will follow the GSi, possibly as soon as Q3 this year.