Hi Michael,

Assuming that the squeak wasn't there before the springs were changed, it sounds like something isn't quite right in the way they were fitted or that the wrong length spring was used. The reassembly of the suspension is very important. I can only suggest you bring it back to the mechanic to have it sorted out. If you did the work yourself then you need to jack it up and take a wheel off and see if you can find anything amiss.

Best of luck.