Recaro Seat Height adjustment

Hello I posted this is Australia but haven’t had much luck so hoping someone here can help.
My drivers (RHD) Recaro CS seat height adjustment is stuck on the lowest position and won't adjust up. So I pulled it out to have a look and there appears to be nothing wrong with the geometry of the seats. I tapped the pinion with a brass drift and it moved so it wasn't bound up on the plate with the teeth the pinion runs on. So it looks like the adjuster has gone. I looked at a Youtube video (not Renault) but it had a similar adjuster and it looks like it is quite a complex ratchet type mechanism and in this case some plastic snapped off so I’m thinking the same thing has occurred for my one. The thing is I can’t find the adjuster anyway. Has anyone replaced one of these before and if so where did it come from? The part number is hard to see in the photo but it is Brose 903872-102 0293204 005 and it says made in Germany. It doesn’t show up Googling this part number. The other Renault part numbers in the photos also return nothing on a search.

Weirdly it's riveted to the whole cross frame. I assumed this was a Renault decision to make us replace the whole frame but them I was looking through a Clio 197 factory manual and it shows exactly the same thing for the Clio sport seats. In the manual it says to drill out the rivets and replace the adjuster than re-rivet. Not sure why as it looks like it would be suitable for bolting. Maybe because the rachet movement would loosen the bolts but I’m sure some Locitite could fix that.

Anyway I need to get this fixed so any advice on sourcing a new height adjustment mechanism would be appreciated.

Here is the youtube video I was looking at that where the adjuster looks the same as the Recaro one....



Incidentally I struggled to get the cap off the height adjustment lever and there was nothing on Google but I worked out if you get a screwdriver in the bottom it just levers off (photos attached).

 

By the way I contacted Brose directly and asked for their help and they said....

As a global supplier to the international automotive industry, the Brose Group does not operate a spare parts business for private customers, nor are our products available through automotive dealerships.
We ask for your understanding that, for this reason, we cannot offer you technical support or direct assistance.

 

Pretty much stuck. Less than 5mm each direction. It feels like the mechanism is stuck.