You can also get regular Marching Bass Drums on EBAY used and a very good price. Many come with case and harness so it is already to go. Most of the ones I`ve seen are Yamaha and a few Pearl.
I believe "
shipping to the UK" was the problem with this. Otherwise, yeah, used marching BDs are relatively cheap on ebay. I shudder to think what shipping across the Atlantic would be for something the size of a bass drum.
Checking ebay.uk, though, I see only one very small (16") older Premier marching bass worth bothering with. Next best thing is a sub-Pearl-Competitor level Premier. Oddly (to me) the german Drum-Tec Parade Line stuff doesn't look like complete dreck - depends on the quality of the BD lugs and shell.
(unrelated: looking at the Drum-Tec site, why can't companies at least copy a *good* multitenor design instead of only the really, really bad ones? Are they just not paying attention? Even cruddy build quality with a decent starting point is better than than cruddy quality AND a horrible design! I mean, they basically have a 90% copy of Premier's snare but don't do a knock-off set of tenors?!? \rant)