Car over the past few days has been making a strange (kinda very slight grinding, maybe slipping) noise.

It happens mostly when I change from 3rd to 4th and to 5th, and when I release the accelerator quickly.

Noise occurs first when pressing the clutch pedal down when changing from 2nd to third, it stops when in gear and clutch is depressed, starts again when change to 4th, and then it starts whenever the accelerator is released in 4th or 5th

How much would a standard garage charge for the whole thing? we talking over the £400 amount?