Not only his essential modesty but his affectionate nature and the frank charm of his manner are apparent in such of his letters as have been preserved.
The association of Bass with Flinders was fruitful in achievement, and their friendship was perfect in its manliness; it is pathetic to realise that when they parted, within a few weeks after the return of the Norfolk to Sydney, these two men, still young in years and rich in hope, ability and enterprise, were never to meet again.
As from this time Bass disappears from the story of his friend's life, what is known of his later years may be here related.

His fate is a mystery that has never been satisfactorily cleared up, and perhaps never will be.

He returned to England "shortly after" the voyage of the Norfolk.

So wrote Flinders; but "shortly after" means later than April, 1799, for in that month Bass sat on a board of inquiry into the Isaac Nicholls case, to be mentioned again hereafter.
In England, Bass married Elizabeth Waterhouse, sister of his old shipmate Henry Waterhouse, the captain of the Reliance.

With a wife to maintain, he was apparently dissatisfied with his pay and prospects as a naval surgeon.