Thanks for the interesting link. I note your long interest in the subject.
Somewhere I once read about Bronze Age trade between Britain and the Mediterranean, even Minoans of Crete.
Their interest is said to have been British tin.
Here is a link showing Bronze Age connections between Crete, Spain and Britain.
None of which, of course, proves anything about Welsh DNA.
It only suggests that Bronze Age connections should not be ruled out, a priori.
Andelusia, Spain, Bronze Age fortress:
Minoan ships: