Your photos of Mike Parkes Maguire Mini prompted me to find a photo of the Maguire Mini we had in 1978.
Mike's car was chassis 001, it had an Arden 8 port 1000cc screamer and was very quick.
Ours was chassis 002, we fitted the engine from our steel bodied car, an 8 port,Weslake 1290cc short stroker on 4 Amal carbs, we spent so much on the chassis, bodywork, brakes and 13" wheels and tyres, (we had 10" wheels on our old car), we couldn't afford to rebuild the engine and box, so it had to go in as it finished the '77 season !!