Well after painting the paper, the room looks brighter. Crucially, almost none of the gaps in the lining paper are visible. Don't know if they just filled with paint, or the paint caused the paper to expand.
I say almost because there's one wall where it looks like someone has drawn a pencil thin line using 4H pencil and only visible up close. It'll be hidden by furniture. A similar thing is where I used ronseal big hole filler where the old lightswitch was. A small pencil thin line 40 mm high which I've sanded and filled. Waiting for it to dry before sanding and painting over.
I say almost because there's one wall where it looks like someone has drawn a pencil thin line using 4H pencil and only visible up close. It'll be hidden by furniture. A similar thing is where I used ronseal big hole filler where the old lightswitch was. A small pencil thin line 40 mm high which I've sanded and filled. Waiting for it to dry before sanding and painting over.