Hi,
I have no knowledge in php, but somehow managed to create some minimal php panel using tvheadend api.
It shows basic info from tvheadend, what user is watching, ip, which client is using ant etc.
And managed to create disable user function, if time is passed (code not yet updated in my page).
Code is on my blog page.
https://evpro.lt/tvheadend-php-admin-panel/
Download: https://config.evpro.lt/tvh-php.zip
You need to adapt that code, put your ip numbers and etc.
If there will be some interest I will update the code and this post whit more info.