SOPP662: Who's the composer of that fantastic G major piece?

This question was sent by  Irineo, and he writes:

“Hello there, dear maestro.
Thank you for your latest SOPP about Unda Maris. I really enjoyed it. But I have a question: who's the composer of that fantastic G-Major piece you played from 21:00 until 23:17? It sounds early baroque to me, but I can't really say whether it's Bach. And what an AWESOME Bombarde 16' does that organ feature! Where is it located? Sounds just as beautiful as that Jacek Siedlar instrument where Maestra Motuzaite also played a recital for which I congratulated her a while ago, if you recall. Keep rewarding us with those great treasures, maestro. Say hello to Maestra Motuzaite for me, will you?
Very truly yours,
Irineo.”