Thanks for all the tips here, I managed to get it working as well. I followed the steps from @theandywaite and had a very similar experience. I did managed to get it done without ODBeleven or VCDS however.
Using the "Car Scanner Pro" app I was able to enable the Google GAL and Apple DIO features, and clear the DLC B201A error. This can be cleared just by choosing Confirmation of installation changes from the Multimedia coding menu, I didn't have to enter any codes with it or do the XOR calculation (done in the app above).
There are several different ODB profiles you can use in the app, I used the "PQ25, PQ26, PQ35, PQ46, MQB: Diesel 1.6 TDI CAYA, CAYA engine" profile, and it seemed to have all the codings needed.
I used a Carista dongle, at first I had a very cheap one but it wasn't able to handle any coding, the Carista one seemed to work find. I also enabled the GEM menu using Carista, but this could probably done in Car Scanner Pro instead. Carista is a horrendous app, I got a sales pitch pop-up on every click in the app even after paying for a short subscription, and it wasn't able to support all the coding steps to get this job done, best to stay away from it entirely.
You get 3 codings in the free version of the CSP app, which is probably one too few to do all of this, but subscription is like £3 so no big deal. Overall it's possible to get this done with a £25 Carista dongle from eBay (I used a blue and white one), and a few £ for CSP.