Didn't you live in Yorkshire or Lancashire at some time? When I lived in Bradford (admittedly this was 50 years ago) I distinctly remember that local folk called the larger, yellow-fleshed variety a 'turnip' rather than a 'swede'. The smaller, white-fleshed version wasn't around so much, as far as I recall back then.
Of course we know the difference, and enjoy both kinds! Here in the SE, swedes are often cheaper, weight-for-weight, than white or purple turnips, and have a good flavour if they're fresh (the ones served up for 1950s school dinners probably weren't....)