Hello Daveonthepad,
You could try the steps here for issues using the buttons or switch on your iPad: If a button or switch isn't working on your iPhone or iPad
If a button or switch isn't working on your iPhone or iPad
If a button or switch isn't working on your iPhone or iPad, here are a few steps that might fix the issue. If they don't, you'll need to set up a repair.
1. Remove any protective films or cases that might block the button or switch.
2. Check for debris or dirt around the button or switch and clean with a soft cloth.
3. If the button or switch still isn't working, is damaged, or works intermittently, you can set up a repair:

Set up an iPhone repair

Set up an iPad repair
Removing any case or screen protector would still help, even if you disabled the buttons. Cases and screen protectors that do not fit properly or are damaged, can cause unexpected behavior on the device.
We would also recommend restarting the iPad: Restart your iPad
As this often resolves simple issues.
If the issue persists, then you'd need to have the iPad examined for potential hardware issue. Contact Apple Support to discuss your service options: Get Support They'd need to take it from here.
Take care.