Take NOTE :
This engine is a 6 pot and is normally very smooth, with or without knackered engine mounts.
Do the check suggested by our friends below for good measure.

The vibration at idle and worse under load......
To me ... this points to flywheel !!!

The flywheel is a dual-mass unit & it sounds like the springs have broken down.
This will cause the outer orbiting part of the flywheel which has the clutch mating surface and starter ring gear to run eccentrically, and even worse under load.
IF it is the flywheel, and this vibration is coming from here, the damage will be passed thru to the release bearing, the main engine bearings, rear seals, gearbox input shaft bearings, primary gear shaft bearings, + gear teeth, seals, and in extreme cases will bend the gearbox input shaft - but the box will be a scrapper by then any way !

You may even notice the the sound of the starter ring gear making an uneven noise as the starter rotates the flywheel. There will likely be an amout of slop take up as you accelerate and decelerate, noticeable more in a higher gear ?

If I'm correct . . . . . and Im sure I am......
You WILL destroy your gearbox and items detailed above if you continue to drive without getting this fixed in a few short miles..... do not drive the vehicle !!!!!

In theory, you clutch fitter will have some kinda guarantee for the work or parts - provided you had the total clutch package fitted incl flywheel...

If you didnt, and the flywheel is as fault, you will be wise to replace the whole lot again, ie clutch disk, release bearing AND flywheel when you do the job again, as each of these parts will damage each other in this instance.

Regards
Grant B