Kettle or just base (see notes) (Ecclesall, S11)

Passed on by someone else who lives in area with high limescale - I've tried removing with vinegar and sterident but not made any difference. There's a mark on side (see photo which looks like rust) which I'm not sure if it's letting through a bit of water. So maybe kettle could be useful as a stop gap or if you are using to boil water you don't drink. Brand is Haden if just the base could be used as a replacement.