It is difficult to move away from rest in first gear.

The car begins to move, then hesitates briefly before picking up speed normally.

Main dealer acknowledges a 'slight hesitation when pulling out of side roads' but claims this is a feature of the manual gearbox.

I am not convinced by this explanation; any ideas ?

Could it be the Blue Efficiency gubbins.Throttle response at all speeds appears to be damped, i.e. there is considerable movement of the pedal before the engine responds.