Can't seem to remove or alter website blocking restrictions on iPhone 6 having given my daughter an old iPhone 6 (latest ios12) to use around the house I'm struggling to unblock certain websites. The error messages are slightly different whether in Safari directly or an in-app browser -
In-app browser says 'You cannot browse this page at &quot;....&quot; because it is restricted'
Safari says 'Safari cannot open the page. The error was: &quot;The URL was blocked by a content filter&quot;.'
She was previously using a 1st gen iPad mini (ios9) and has her own limited/child Apple ID. On the iPad she would attempt to visit a website and upon being notified it was blocked, you could click a link to enter the parental password and unblock that site. Since restoring onto the iPhone it seems some of those restrictions have been passed on, in that some sites are accessible but others aren't. The problem is that when seeing an inaccessible site on iOS12, there is no direct link to unblock it.
Screen time was not set up initially, however upon turning this on, and either setting content restrictions to completely disabled, or having it enabled but having web contact set to unrestricted, or having web content limited but with specific urls in the 'always allow' section, I'm seeing the same behaviour whatever I do.
Where else can I adjust these types of settings?
Edit: I've noticed in settings/safari that favourites are greyed out and set to 'allowed sites' I can view any site which is already listed in favourites but cannot find anywhere to edit the favourites.
You are using the new ScreenTime for iCloud (this is different from the local ScreenTime you have disabled). It sounds like the local restrictions on the iPad has been passed on to the limited Apple-ID and then stored on iCloud. The limited Apple-ID has a builtin ScreenTime which stores its settings on iCloud and overrides the local ScreenTime.
There are two ways of controlling ScreenTime for iCloud.

From another iPhone with a parent account signed in with. Open settings app, click on parent name at the top. Scroll down to Family Sharing and select your child's limited Apple-ID. At the bottom you can turn off ScreenTime for iCloud. You may also from this screen change limits (e.g. allowing websites e.t.c.).
From the limited iPhone. Open settings app, click on the name of the child at the top. Scroll down to ScreenTime and select the child name again. Here you can control ScreenTime, but not disable it.

The setting you are looking to change is located in &quot;Content &amp; Privacy Restrictions&quot;/&quot;Content Restrictions&quot;/&quot;Web Content&quot; user the subpage described above.
The name &quot;ScreenTime for iCloud&quot; is a name I made up in order to distinguish with the local ScreenTime in this answer.