I bought a set in Chester earlier this year and they're very good. Unfortunately I can't remember the make, so I didn't come back to you earlier. Perhaps you can get Mr Happy to pop into the shop and ask what short-scale acoustic bass strings they keep.

I should have warned you off the flatwounds, though. They're usually a bit quieter than rounds. I find that, as I'm playing much less bass than I used to, my fingers blister more easily if I'm playing hard. I think that you might end up playing the flats harder than you want to and so lose the benefit of comfort.