Dash vibration

Hi there, a newbie here, I've bought a 16 plate Superb SEL Executive Estate and like many others, have a centre dashboard vibration at about 2000 revs which disappeares moving past this rev range. 

I've read the AC pipes behind the dash might be at fault.

However, my local mechanic ( who I've been using for years and trust implicitly)  says that it's worn engine mounts. It's a pretty involved job, dropping out the sub frame, pressing in new bushes, then the top engine mounts. Has anybody come across this vibration and found the engine mounts to be the cause ?

Thanks.