Re: So then
"This means our courts can't be overruled by another court over the channel [...]"
The ECHR is not part of the EU. It was established with the support of Winston Churchill after the war. The Tories have spoken about rescinding that agreement and possibly the UN Charter too.
Our elected Governments have no difficulty passing laws - which they do frequently no matter what public opposition. If it gets contentious they slip it in by adding details as secondary legislation which is almost like ruling by decree.