I think the Family models were in fact four seaters. A couple of F types here as spotted at out local M3W club meet, which may be the models you were considering.
I understand they typically employed Ford engines starting with the 933cc 8hp Y type and later the British Ford Popular 1172cc E93A engine of the 1950's developing 10hp. Both were four cylinder side valve engines with thermo-siphon water cooling. I believe the similar successor 100E engine was/is a popular retro-fit, which was fitted with a much needed water pump.
