How do I get it off?

I sorted this ok.
Get little bottle of acetone from the chemist, Boots do it for about £1.50. Put it in a tiny bowl and soak your nails in it for about 10 / 15 minutes. My gel shellac polish came off without difficulty. It's easier than putting soaked cotton wool pads on finger tips.

Soak cottonwool pads in the remover and place firmly on the nail. Leave a while without rubbing.

It wasn't a gel polish, no. And it's not stained as such. It just won't come off. As if I'm trying to remove it with plain water instead of nail polish remover? Although oddly it's worked on some of the nail but not others.

Was it a gell polish you used ?
If you file the surface of the polish so in effect rough it up it allows the remover to soak in.

is it stained, or just big flakes of it?