Caravelle slow up to 2000rpm

[FLMG27]

Hi folks, got a sick Caravelle 1997 2.5tdi ACV.
Its really slow to accelerate up to 2000rpm then takes off no problem.
There are no fault codes but I did find the start of injection value is wrong, here's what it says:

ENGINE SPEED 720RPM
START OF DELIVERY (DESIRED)( BTDC) 0.8
START OF DELIVERY (ACTUAL)(BTDC) 2.7
DC START OF DELIVERY VALUE (%) 3

Is this a case of rotating the pump to get the value correct or do I need to adjust the belt?
These were done recently and has made no difference to the way it drives

Thanks for any help!