Help with NC built in code Collabora behind apache reverse proxy

I am having trouble getting snap NC built in code Collabora behind apache reverse proxy to work.

Collabora built in code is installed and working on same machine as NC when just accessing via the IP.

But when attempting to use it behind an apache reverse proxy I just get a white page.

The setup is:

NC on 192.168.1.20
Apache on same network/subnet reverse proxy turns SSL to non SSL and passes to 192.168.1.20

Site conf includes:
ProxyRequests Off
ProxyPreserveHost On
ProxyPass / http://192.168.1.20/
ProxyPassReverse / http://192.168.1.20/

Settings in snap NC conf:
array (
0 => ‘192.168.1.20’,
1 => ‘192.168.1.webserver’,
2 => ‘https://my.domain’,

And also
‘overwritehost’ => ‘my.domain’,
‘overwriteprotocol’ => ‘https’,
‘overwrite.cli.url’ => ‘https://my.domain’,

If anyone has any tips on getting this configuration working it would be great to hear as I am obviously missing something and I couldn’t find any instructions for this type of setup.