My Seven is RHD and hasn't been a problem at all. My wife was a little concerned being on the left with the traffic and had to keep "reminding" me to "get over."
I just restored an 86. Cortina engine, single downdraft Weber, front disks and drum rears. Built in England and imported (not by me), RHD. It is great fun to drive, I'm not a racer, so the sidedraft 4 is all I need.
I just restored a Westfield Seven I'll post a picture as soon as I figure out how. We found a plate on the front cross member. AH.86.SE.041 Does anyone know what it means?