1.9 AWF pd vibrating when accelerating?

[JonesyB5.5]

Hi all, after a bit of advice on my recent purchase. Car is a 2004 PD 130 estate. The issue is that it vibrates quite badly when accelerating at certain loads from about 2,000 rpm upwards when using more than a light throttle opening. The engine is smooth at constant revs and idles absolutely fine. For reference it's had an egr and cat delete, new oem clutch and dmf, replacement injectors, new cambelt kit, water pump and thermostat. It's done 161,000 miles, uses no oil or water and otherwise runs beautifully. I'm baffled. By the way it vibrated before all of the above was fitted. Any pointers much appreciated.