The oil dipstick had broken off and stuck in the oil chamber. The
whole engine had seized and, to cut a long story short, it was a sad
day in toyland .

So I bought a new McCullough (with a Briggs & Stratton engine) from
Argos and I'm back in business. I wonder, though, if someone could
explain exactly what the different oil types (30W,SF etc) mean and
which is best. Also, will some oils make the painful process of
starting via the pull cord easier?

Happy mowing to all.