My question is: Are xbox accessories from other regions (such as this) compatible with UK xbox 360's?

Anyone know? If that's the case, I'll be buying all my accessories there.

Yup they sure will, for M$ to make controllers, memory cards, ect. region specific they'd have a mega disaster on their hands, not to mention the sheer stewpidity of it.

That does exclude HD cables (Component vs Scart) and the Power Supply (110v vs 220v), those things are region specific.