Thank you all for the replies posted.

simont wrote:

Have you tried 2T in the fuel????

oldgeezer wrote:

If diesel is leaking past the injector as the rail is under extreme pressure, some fuel will leak into a hot cylinder and attempt to ignite, hence the little hump as it shuts down.
Sometimes a badly worn dual mass flywheel can also have a kick effect.

alex_pescaru wrote:

The electronic throttle, if malfunctioning, can lead to symptoms like this.
The ET is used to prevent engine shudder on engine shut-down and for limiting air intake during DPF regeneration.

No DPF here (lucky me ), but the ET malfunction is precisely what I thought first anyway.
Thanks for sharing the link, I'll show the page to the techs.

my Skoda diesels had a anti-shudder valve which prevented shudder on engine turn off - it was activated through vacuum in turn controlled by a electronic controlled vacuum valve block. but i dont know if the FL2 has this too. The control block failed on our Fabia VRS and similar symptoms developed.

Hello,

I took a while, but I wanted to be sure.
The engine mounting was broken, and had to be replaced. So far so good, I'll drop a message here if the symptoms return.

Thanks for all the advices and your help. In particular, using the injector cleaner was a good idea anyway. After two doses, fuel consumption dropped from 8.5 to 7.4.

Took mine into the dealer today with exactly this problem - shudder on shut down, and also feathering of revs under load. Dealer has diagnosed faulty throttle body.