Neil, I don't believe I've ever seen an actual turnip. What do they taste like?
Turnips resemble rutabagas, but (normally) much smaller and much milder. They really don't have much flavor at all, which is why they are ususally served with generous amounts of butter.
Rutabagas can be whipped: "Scottish "neeps" are rutabagas (B. n. napobrassica). The name comes from the Swedish "rotabagge", which is why this vegetable is also called a "Swede" or "Swedish turnip" in England. Absolutely do not use American turnips as a substitute, as the taste simply will not work as well. To prepare the neeps, peel a fresh rutabaga and cut into 1" cubes. Boil, drain, and whip them into a frenzy with some salt, pepper, and ,of course, butter"--I've tried them that way and found them quite delicious.