Mk1 Technical : Brake squak / knocking noise after new spring

They found it had a broken front suspension spring.

They couldn't get the part, and as I was in a rush, I took the car away, got a spring from Euro car parts, and took it to an F1 Autocentre to fit it.

I went to pick up the car, and straight away when driving it away, there was a scr*ping noise. I took it back, they jacked it up, and the spring wasn't properly seated in the strut. After rotating it, I drove away again. However, there is still a knocking / squealing noise when I brake. I took it back to the garage. They clearly didn't want to know, told me I had bought the wrong spring, and to give it a while and see 'how it goes'.

Tried heavy braking from speed in case there was debris between the pads and disc.

Got home, took the wheel off, had a really good look. The spring is solid, all the connections are tight, everything appears to be fine. But the noise is still there when braking.

Any ideas? Please help!