What does "the basis must still hold" actually mean?
That whatever qualified you originally has to still be true. If you obtained the visa through property and have since sold it, that basis has gone. If you qualified as a licensed professional and the licence has lapsed, the same applies.
This catches people who treat a long-term visa as permanent. It is long-term, and it is conditional.
- Property sold since the original application changes the position
- A lapsed professional licence weakens a professional category renewal
- A change of employer or field may matter in some categories
- Check the basis a few months before expiry, not in the final week