The rule you have mentioned applies to allowances where they want to be sure that its not reimbursements. Benefits in kind are not allowances i.e. 'they are not in form of money or of direct cash value' which is why they will not be mentioned on payslips and not transferred to bank account. Instead they have cash equivalent provided by HMRC that is considered to be of direct monetary value. Which means HMRC have provided a figure to me and my employer saying the benefits i have are worth £xxxx and I have paid tax on this through my tax code.
I know this is confusing enough as to how its classed as earnings however before applying I have clarified with my employer, accountants and also HMRC. All said one thing that my Total Earnings = PAYE salary + cash equivalent of benefits. My payslips and bank statements confirm my PAYE salary, and for benefits I have put employer letter and P11d.
I'm only worried about not having sent a letter from HMRC directly, but HMRC yesterday again said that I can use p11d or tax code documents. My mistake was I didnt put tax code documents, but now I want to send them as additional evidence from HMRC confirming benefits. And I'm worried if they want a confirmation from HMRC which I have not sent and also if i send now will it be too late?
Regarding BIK earnings HMRC clearly has defined rules -