Hi Declan,
Welcome to the forums :-)
In GB's preferences, choose [Advanced] and set the Audio Resolution to best (24bit).
Make sure "Auto Normalize" is turned OFF!
Now solo a track and choose:
Share > Export Song to disk...
In the Export window turn OFF "Compress". You want uncompressed audio!
AFAIK GB only exports uncompressed audio in .aif format. Pro Tools should be able to read aif files no problem.
Cheers
Rounik
btw, posting the same question in multiple threads can cause some confusion. I've deleted the thread you created in the Pro Tools sub-forum.
Best,
R