For those who are interested, here is a command line utility to extract and convert GBA Doom 2 maps to PC format from a ROM file.
The converted maps will require BSPing.
I have provided a MAPINFO to match up the maps appropriately.
GBA differences to note can be found on the wiki:
Doom II for Game Boy Advance
I should note if anyone is going to play through these maps, that I have no idea which maps work or don't.
I do know the Grosse is not completable without re-tagging the exit door sector.
The maps are direct conversions and come with any problems that the maps originally had.
e.g. ghost secret sectors.