He can make that case to the investigating committee. If Farage finds that inconvenient then, well, the easiest way for him to avoid such scrutiny in future is to declare any large amounts of money he receives. Not that difficult, and surely in the public interest to do so.

The standards committee has not yet made any ruling. It would be one thing for Farage to object to a specific ruling by the committee, but to object to the entire concept of a large undeclared personal gift being investigated simply shows a contempt for Parliament.