Never you mind is a playful refusal to answer a nosy question. Never you mind where I got it.
The extra you makes it teasing where never mind would be dismissive. It is used most by older speakers and to children.
1phrasenever you mindA playful refusal to answer a nosy question.
“Never you mind what it cost.”
never you mind is a phrase.
Practised in Small Talk & Everyday Phrases