Alvin,
Had a similar problem with mine (exasperated with the QLD weather)
When I had the cockpit reupholstered took the opportunity to line the footwell with insulation matting.
Vastly improved things - now I have the soft feel of leather rubbing my left leg
Prior to having the matting fitted (which is easy enough to do yourself (cut it and stick it) I was thinking of insulating on the underneath are of the car, but did'nt need to