Saw the specialist this arvo. Yes indeed: we're pretty much certain that what I've got is a mercifully mild case of
Crohn's disease. (And, as I'd speculated, it couldn't have been diagnosed without a capsule endoscopy!)
Crohn's can be treated with drugs, but they're hard-hitters: corticosteroids and immunosuppressants, the sort of medications you only take if you seriously have to. Luckily, we can most probably treat my symptoms with supplements, and - if I'm lucky - with over-the-counter tummy medicines in place of the Questran and its evil side effects. We shall see! :D