Listed building consent for internal alterations — what counts as "alteration"?

We live in a Grade II listed cottage and want to open up the kitchen/dining room by removing a non-load-bearing partition wall. The wall is clearly a later addition (1930s brick, totally different from the original timber frame).

Our architect says we definitely need listed building consent. But I've spoken to two neighbours who did almost identical work and neither of them applied for anything.

Is there any nuance here? Does "like-for-like" repair not need consent, but removal does? What's the actual risk if we just do it?

You definitely need Listed Building Consent for removing ANY internal wall in a listed building, regardless of whether it's original. The listing covers the whole building, not just the historic bits.

Your neighbours who didn't apply were breaking the law, plain and simple. The fact that they got away with it doesn't make it legal. If you do it without consent and the council finds out, they can issue an enforcement notice requiring you to rebuild it.

That's sobering. We'll apply properly. Better than the alternative.