Thanks @texnixe, this did not have any effect.
and they replied: The specified verb permissions, as shared in the KB, were set up by default. I have modified it to allow all verbs
still not working - is there a way I can test if PATCH requests are blocked?
Can you do other things in the panel, like creating or deleting pages? Changing the Uploading files?
no, all results in the same error.
Have you checked your file/folder permissions/ownership? If you can’t do anything in the Panel, then it’s probably rather a permission/ownership issue.
What a timing. I currently have the exact same problem on a Host Europe server:
@texnixe I just transferred the domain to this server and I’m still hopeful my issue will be solved automatically once I wake up tomorrow morning. Maybe it has something to do with the relatively fresh dns settings.
Searching the forums for this error and finding this new thread made me think it could be the same thing. But let’s wait a few hours.
Good night and good luck, then. 
what permissions should I be checking - the content folder? Does kirby not do a permissions check during the panel install?
Yes, I think it does check if they are writable when you install the Panel. Have you tried to do that? I was assuming you uploaded a project with the first Panel user already installed.
I zipped up all files from the dev server then extracted them on the new server. I installed the panel and there were already user accounts. The panel works, it just will not save anything.
glad you sorted it @thguenther - I don’t think this can be a dns issue for me as it is not a new domain.
Could you please remove the Panel users, allow Panel installation in your config and try and install the Panel on the remote.
just delete the site > accounts folder?
On panel install this time i get:
Kirby requires Apache , Nginx or Caddy
I think the accounts folder must exist (not 100% sure), but the folders inside.
That sounds as if Kirby doesn’t recognise the Server correctly.
yea,h I think i might just have to abandon this host 
After lots of back and forth with the host - they worked out that PATCH request were blocked. I can save everything now.
I am still get 404 errors on pages like this: http://mysite.uk.com/edit/pages/home+francesca
Could the + symbol in the url be the cause?
No, the plus symbol is perfectly alright. 404 errors when just visiting the page or when trying to save?
For any other poor soul trying to install kirby on windows server I added this to my web.config file:
<security>
<requestFiltering allowDoubleEscaping="true">
</requestFiltering>
</security>