B&D Strimmer - glue to hold on cassette mechanism

I have and old B&D strimmer with a plastic cassette holder and an orange cartridge for manual feed nylon line.

It ate a load of garden string and I had to take the black casssette off to get at the metal shaft and untangle the string.

Now this is a reconditioned (allegedly by B&D) strimmer which was given to me as a present by the in-laws so I have no proof that it was in original condition.

The black holder prised off the shaft, but on investigation it didn't seem to clip onto anything (although there are clippish bits under it) and it seemed to have been glued to the shaft.

So - looks suspiciously like a bodge and not B&D original but who knows?

So does anyone know:

(a) is this the way the cassette holder should be fixed on (b) if so, what is an appropriate glue to use?

Cheers

Dave R