I've bought this great instrument and upon further inspection found that it follows a slightly different layout than the Wheatstone layout put forth by concertina.info, being with one single note difference. It might be an error in manufacturing of my unit, so please reach out to let me know if this layout matches yours!
The single difference to the Wheatstone 30 button C/G Layout I found is the farthest left bottom D on the pull tone. On my unit, this is rather an A. Here is the updated layout:
Please continue to enjoy playing your concertina!
Simen