Identifying the correct brake parts

Hi there,

Some of you may have already seen me trying to get my MK1 Scirocco 1978 back up and running

I'm struggling to find a suitable replacement brake servo, the original part is labelled:

ATE 03.6132-5701.4

An american guy on Facebook, told me that this part is available in most car parts shops, but when I asked more about it, he suddenly went quiet, oh how I love social media !!

I can't find an identical one on sale anywhere so I went digging around to see if I could find an alternative part number or any details.

I found a big pdf document called ATE_classic and in there it states that it is a T51 type 7" servo.

When I googled images of a T51 type 7" brake servos, there were lots of pictures of what look like very similar items.

From the images it's hard to see if the fixtures are compatible, etc.

Any tips? I've looked also at the upgrade thread for a mk2 16v booster and I wouldn't mind trying that but most important to me is to find all the compatible part numbers for a solution that will allow my car to have enough brake power to get through a technical inspection.

Thanks for any help