Quite right, Mike, two seaters only. I guess they have got a bad reputation in England, from the time those french cars had to compete against the fantastic Lotus'es. But honestly, apart from "indice de performance", what could be expected with a weak Panhard engine?
I use to drive a HBR Super Rallye, but with a 900 cc inside running on two carbs, double ignition and 3 stages oil pump. It works fine, cornering is good but in no way comparable to Hethel's machines.
The biggest mod' I saw was a Panhard fitted with two Norton Manx heads. Probably only 3 engines were ever made, all of them couldn't prevent the crank to go out from its case with no advice…