Do I need to include the vampire of my private medical insurance if it has already been taxed?

I need to pay the High Income Child Benefit Charge and I am completing a tax return for that purpose only. I am employed and pay tax by PAYE monthly. I have private medical insurance as a benefit through my employer, and I am asked to input that value which can be found on the P11D form. However, my employer informs me that we are taxed monthly on the value of the insurance, so there is no P11D. It therefore seems that I have already paid all of the tax due on that insurance, so do I need to include the value of the insurance when completing my tax return? I obviously don't want to pay twice on it, but don't know whether it is relevant for the purposes of calculating the value of the HICBC that I need to pay. Thank you.

Hi Stephen,
If your medical insurance is taxed at source (as your own medical insurance is), you do not need to declare this on your tax return.
HICBC is based on your Adjusted Net Income for the year.
You can read more on how ANI is calculated here:
Personal Allowances: adjusted net income
Thank you. 

If you look at the total earnings shown on your P60, I expect you'll find the taxable value of the benefit has already been included within that figure, in addition to your gross salary. That's how it gets accounted for, without a P11D.