New iPad won’t update to new iOS due to “being restored” any ideas?

From the default WiFi name, I deduce that you are a BT Broadband customer. As such, you’re likely using BTs DNS servers - which are notorious for unexpectedly blocking access to some resources. Whilst this may not be the issue, it doesn’t hurt to eliminate this as a potential source of issues.

I suggest, therefore, that you manually input DNS Settings for your iPad. For this exercise, we’ll use the Quad9 DNS service - a good, secure, reliable DNS provider:

Settings > WiFi

At the top of this settings page, will be the name of your currently selected WiFi network (BTBHub6-H2X9). At the extreme right of this field is an “i” icon. Touch the “i” icon to reveal a further page of network settings.

Scroll down the page to the section entitled Configure DNS; it will likely be set to Automatic. Touch - change this to Manual - now touch the “+” button to add a new server address.

Add 9.9.9.9

Repeat this process to add a second address - 149.112.112.112

Delete any pre-existing DNS Server addresses using the corresponding “-“ button.

You should now have two DNS Server entries - 9.9.9.9 and 149.112.112.112. When all is as expected, touch the Save button at top right.

Now force-restart your iPad:

https://support.apple.com/en-gb/guide/ipad/ipad63d30b5a/ipados

After your iPad reboots, retry the update.

Perhaps you could be more explicit in your description - or a screenshot of the error you see - so we can offer some constructive advice.