Airbag Control Unit

I've come to the conclusion that I need to replace my airbag control unit (see other feed on the 65535 error code).

I used the VAG-COM scanner to check the part number and it came back with 6Q0 909 605 H. The Ross Tech website stated it's the 6Q0 909 605 A units that have the problem when scanning with a 3rd party scanner, so I'm a bit curious as to why it's telling me its the H version. I was under the impression that the letters denote the release version making the H a more recent release then the A. Which again wouldn't make sense as its a 2000 Fabia so should have an earlier version.

Is my thinking correct? Also would I be able to purchase a 6Q0 909 605 D for instance and it'd work just as well as a A or a H or anything in between without any compatablity issues. I know I may need it scanning and activated or something, I'll leave that up to a garage with a proper VAG-COM scanner this time lol.

Next question, where is the unit? I've taken the centre consol bit around the handbrake off and the black plastic around the centre near the feet (tunnel i think?) but I can't find it. I haven't had much time to look for it as the light keeps fading by the time I'm outside working on it. Damn that thing call the Day/Night cycle that has to happen lol. The Haybes manual shows a picture of the unit but doesn't really show where it is, so none the wiser there! Anyone know where I should be looking?

Thanks in advance!