Okay, I don't in general see "duplicate" as implying this, but I take your point, and was wondering if that might be the etiquette here.

I also think, on reflection, that you are right in this particular case (given there are no comments on the previous duplicate) so, thank you also for clarifying.

I suppose in the future an e.g. "[Previous discussion]" tag would be more appropriate, providing comments were made, otherwise, just say nothing and leave it to HN.