I think you should be able to just separate them with an "|" symbol.
Something like:
"(\+44\s?7\d{3}|\(?07\d{3}\)?)\s?\d{3}\s?\d{3}|\(\d{3}\) \d{3}[\-]\d{4}"
You would probably have to remove the formatting options if it is auto-formatting to add parenthesis as well.