We stopped supporting GPAW in the Scripter 11.8 but accidentally left the install script (and the tutorial). We tried to keep up with their releases, but it never matched, so you ended up having an old version always in ATK. And besides, "our" shipped version of GPAW was serial, and GPAW is a code you really want to run in parallel - it's honestly speaking dead slow unless you do (but it scales great in parallel!).
The current status is not all that bad, however. In ATK 12.2 there is a "Custom Scripter", somewhat hidden, but you can get to it via the Tools menu in the main VNL window, and choose Custom Scripter there. In the tool that opens up, choose "GPAW" from the "Scripters" menu, and you will have more or less the same functionality as you had in the old Scripter in VNL 11.2 and before. It's just that instead of running the script directly in VNL, you export it and run it in a standalone GPAW version.
So, you have to install GPAW (and ASE) separately, but as mentioned above you would have had to do that anyway, also before, to get it to run in parallel. But you will benefit from being able to use VNL to build the geometry and set up the script.
We will work in collaboration with DTU to extend the functionality in the Scripter for future versions, and also to be able to read the output files to visualize the results. In you want to have these features sooner and some in particular, it would be a good idea to tell the GPAW developer group to gain some momentum for this project