If it squeels  whilst the clutch is depressed/being depressed then it is
probably the clutch plate thrust bearing.  Was this replaced when the new
clutch was fitted.  If not then I would get the garage to replace it free of
charge as, for the sake of £10 odd pounds, they should have replaced it when
the clutch was done.  To replace the bearing the gearox has to come out of
the car again.

Nick /////