Hello Bon-Scott. coolrussy and Norm
Well, the Regal was always considered a premium or flagship domestic mower.

The name 'Super' first appeared in the 1960s - and they were the 19" and 21"
side-discharge models. In the early 1970s, my favourite was the 3210 or
Super 4 21.

When Rover changed to the high arch side discharge designs, they appear to have
dropped the name 'Super' in favour of the 12110 19" Prince and the 21" 13110 Prince.
For a short period, the 13110 Prince sold alongside the older 3210 Super.

Yes, the Super Four 19 and 21 were always considered commercial grade, and
would often appear in publications alongside ride-ons.

Cheers
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Jack