I have a bag of Blackpool that I haven't gotten around to opening. One of these years...
Tried everything from esoterica. The three big Penzance, stonehaven, and peacehaven are beyond over rated. Keep looking and you will find the rest.
I don't think Stonehaven is particularly overrated, but I haven't found a blend that was life changing, ever.
I do agree that the best of them, at least for me, are not the ones that people are scrambling over. I liked Dunbar better than the three you mentioned, though the batch from 2021 was crap, so that's it for Dunbar. And I like Tilbury and Dorchester. Brighton is another one that I like, but Kinghtsbridge is a complete snooze for me, like there's no there there. I have a bag or two of the others, but haven't gotten around to trying them, and may just sell them off.
At this point I have plenty of good stuff, like Motzek Strang, as well as a number of McClelland blends, and am not particularly curious about trying out more stuff when I already have some of the best there is or was. It's an age related thing for me, I suspect. My curiosity is moving on to other things.
That said, I do have some blends available only in Japan that my son is bringing back with him, and I'll give those a whirl, just because.