Scottish accents are far harder to do, most are awful and sound like shrek

I think others have had that opinion. Seems like people see Karl in roles everywhere. LOL Just the other day I was watching Ghost Rider and said, OMG they should reboot this with Karl!
The only time I recall him doing an English accent was in Almost human his character did it as part of a disguise, and it was ok I guess. I'm American so I couldnt say for sure, it wasn't like an accent you'd think of Bond having tho it was cockney, maybe? He does an okay to pretty good job with the American accents tho (I can occasionally hear a bit of Kiwi in his accent in certain roles and words but in general he's fine), so I'd assume he could learn to do the right English accent if he needed to. The same with Scottish.