P11D for owner managed companies

We have a number of small owner managed companies who pay for a number of expenses personally which are incurred wholly, exclusively and necessarily on behalf of the company and do not attract a tax or NI liability.  Expenses for example are telephone calls, stationery, stock etc.

In practice, is it necessary to fill in the P11D?  What is the view of HMRC of not filling in the form, if they became aware of it in an enquiry?

Any experiences with this situation gratefully received.