Only random musing really- but I've people staying at the moment. Been a while since they were here and anything that's changed in my house that they have spotted they have said positive things and it finished off with "very posh". (Not big costly changes either.)
Context certainly suggests that it's compliment. But it just seems such an odd way to say you like something, as to me "posh" isn't something to aspire to - also don't think I've heard (or just not noticed) anyone use it to compliment something.
So while I sit about this morning waiting for eveyone to get up I thought I'd asked MN if it's a thing - or if I've a pair of odd linguists in my house. 😂