iMedicare will do the demo over a videocall during COVID-19, if you're still interested (or if the remaining ball is still interested;-). I think the details are on their website, but PM me if you can't find them.
I presume you are referring to their Surefit rings. The pump comes with one, but you should get a pack with 3 more if you got it on prescription, and in theory, the 3 ring set should be on a repeat prescription, although you aren't meant to cut them off after each use.