Hi Kilou
I have now done some work on my car. Removed the two lower engine mounts and found that they had been replaced and installed the wrong way, back to front. This was done before I bought the car. To my disappointment it made no difference to the vibrations after having reinstalled them correctly.
Next was the upper front motor mount (timing belt end) and after removal I found it was in a bad state. It has now been replaced and the vibrations are gone.
The moulded rubber was slightly beefed-up on the replacement part compared to the old one however it was ordered as a replacement part for my year model 1997.