Martin...Trevor...thanks to both of you for your efforts, you were both close. Very close...but no cigar.
MotorFlotes are basically a motorized pontoon, I know that there was at least one operating in Poole Harbour in the late sixties/early seventies, but that's more or less all I know. I've had my spies out looking, but to avail...so, I guess they were withdrawn and lost in the mists of time.
Thank you both again, I appreciate your assistance..