Registration wrangles

I have just taken over a new client that buys and sells computers. He is a bit of a character and tends to unnecessarily complicate his business organisation often to impress clients and friends.

He is a director of seven companies six of which do not trade and are dormant.

However to my horror I have discovered that the VAT registration for his business is actually in the name of one of the dormant companies and to my further horror my client has confirmed he knows about this but takes the view that as long as the correct amount of VAT is included on a return and is being paid to HMRC it does not really matter which company is registered.

When he issues a sales invoice he shows the correct company name that is trading but the VAT number...