I replaced the Two trim parts on my Gear lever recently (for chrome ones).
There is a small plastic lug on the front trim that sits in a small hole on the gear gaitor unit - near the Left edge.
To remove it, you need to wedge your flat bladed screwdriver between the plastic gaitor and the plastic trim you are removing. This will release the plastic lug from the hole it clips into, then simply slide the Trim part to the right i think, and it will slide off.
Fitting the chrome trim on is then very simply. Slide it on, until it sits centrally and you 'feel' the lug fit into the little hole on the end of the gaitor.
The job really does only take 5 minutes to replace both Trims. But thats when you realise
how to do it!! It took me almost an hour before i worked it out!
Who needs a Rubics Cube when you own a
SEAT Ibiza!!