I have a couple of fluorescent light fittings in the house, each
containing two fairly standard tubes and two 120 volt starters. I
know the starters need to be 120 volt ones because I discovered a few
years ago that 240 volt ones won't start the lights.

I think I need some new starters again, but every electrical &
lighting shop I've tried so far doesn't have them, and a quick WWW
search only shows them in the USA (where they are obviously useful).

Are double-tube fittings wired this way obsolete now?