Problematic filter is:
||velaro.com^$third-party
This filter is breaking the live chat ability on the website:
https://www.nhsinform.scot/webchat
In specific, the ability to click "chat to someone now"
Adding the following whitelist fixes the issue:
@@||velaro.com^
Note: Multiple resources are loaded from multiple directories on this domain.
A whitelist would need to be quite generic.
It might be better to review why this block entry exists in the list at all.