If I remember correctly, during the production process of Ibiza 6J different types of Xenon headlights were installed in it (maybe I'm wrong), and I also think I remember that one of the BCMs used for one of those Xenon headlight types is the BCM that you currently have installed. 6R0 937 088B (Re4).
Do a search on the net ... (Part No SW: 6R0 937 088 B HW: 6R0 937 088) ... maybe you will find some autoscan of a 6J with the xenon headlights installed, ... and the unit for the automatic headlight leveling.
I recommend that you contact iichel
, he had a similar situation with his 6R "Bluemotion" ... and because I'm sure you will understand each other perfectly (NL).
The heated seats are highly recommended, it's a great upgrade.
Here is a link to the parts catalog in case you have to look for the parts you need, learn how to use it and everything will be fine for your upgrades.
Here is an example with a BCM 'F' later than model 'B' but in essence it is the same: (...with module/unit '55')
https://forums.ross-tech.com/index.php? ... ost-113148
Well, it's a very strange post, but it confirms my suspicions ...
By the way, I would have fixed that problem in 0,1 sec ... OEM way ... but I'm not registered on the ross-tech forum.