Most British cars were designed with the export market in mind. Many had central instrument panels, such as most Jaguars of the 1950s, later Morris Minors, Minis, Humbers and Hillman Minxes. Others had a dashboard with equal sized holes for the speedo and glove-box, such as the early Mark 1 Consul and Zephyr. Rootes' artwork in their brochures didn't even include a steering wheel, so that brochures were applicable all over the world. Minis were so easy to convert to either side; racing driver Peter Manton used to get his mechanics to put the wheel and pedals on whichever side so he could lean into the door depending on whether the track was clockwise or anti-clockwise. Apparently it took very little time. My Austin 1800 has all the holes in the dash for left-hand drive - the earlier ones had extra holes with rubber grommets for the windscreen wipers. Most MGBs were left hand drive, so converting an early one back to right hand drive is relatively simple. Nash Airflytes had a centrally mounted instrument panel, which would indeed have been hard to move the speedo across, so that Mum wouldn't be aware of what speed they were doing.