Thanks for the work around.
For a device that cost me £1,200 that’s a very time consuming and lengthy process I’m not willing to do.
I have moved back to my old iPhone 6 and await an offical response and fix rather than doing the work around.
The whole point of restoring from backup is to make it easy and quick to switch phones - the solution posted is a work around, not a fix. Apple need to sort out the issue, inform customers there is a BIG problem (currently) with their new device, and advise customers that have already purchased when a FIX is expected.
Until then, I will not be using my new phone.
PLEASE CAN NO ONE EDIT THIS POST. THIS IS A FORUM, AND THIS IS EXACTLY WHAT I WANT TO SAY.