On the Wifi side - yes, provided that you can specify "UK" in the configuration setup - this sets the number of discrete wifi channels (differs significantly around the world).
I have yet to see one that is not user configurable.
I don't know about the ADSL part - I'm sure that others more knowledgeable will confirm.
The AC adaptor would need to be replaced, I think - both because of voltage and plug.
Your returns / warranty replacement would be a pain, too.
SD