I'm wondering why being UK auctions would invalidate a price estimate? Or is it because of the variations between some of the releases? Because in general they were sold here too, that shouldn't distort the valuation much.
That said, I'm not sure how in demand they are as a set as a whole. That generally influences the prices. I only have one, I think Singing/Sweet Pocket, because of the hair variation that's more common in the US release compared to the UK. I think she cost around $60. But that was pre-pandemic prices. I'm not sure what that would be now, since COVID seems to have massively distorted the price of everything.