[Da_Shrimp]

Some Scottish men's Y's are remarkably similar to those of southern England.

Depends which bit of Scotland the men tested came from, I should imagine.
IIRC, the Angles were colonising what is now southern Scotland at exactly the same time as the Scots were arriving from Ireland.

[WoofDog123]

"IIRC, the Angles were colonising what is now southern Scotland at exactly the same time as the Scots were arriving from Ireland."

I was going to add when I read your comment that Lowland Scotland is full of Old English place names (i.e. Athelstanesford (Æþelstanesford) somewhat west of Edinburgh).