Apparently my Mum had one of these when she was pregnant with me, my Dad bought it because it had an automatic gearbox which was easier to drive being so big. Not that I remember of course. And after that, she never went back to driving a manual.
That is a beautiful machine. My son-in-law had a race-tuned Manta and he loaned it to me for a week while he did a big job on my Carlton. It was wonderful. A beast to drive, impractical in busy traffic, but on the motorway and country roads it was amazing. I didn't want to give it back.
My dad and I used to go looking at cars probably once a month. We both liked the Manta. I seem to recall a race series for them for at least a year or two too.