A quick Google shows Thomann have sx900 at £1744, Inc shipping. Having just bought GNS-01 speakers from them at £277, much cheaper than UK price, I think was worth it; However, I don't know what the risk factor is in event of any warranty claim.
A&C Hamilton have sx900 new at £1999. They also list used ones at £1499. My previous (new) sx900 was bought June 2023 for £1700. (Traded in this March for Genos2). So, new ones have gone up quite a bit in the last year. With hindsight, i could have bought a secondhand Genos 1, and still traded it in for same price!
So I'm suggesting you consider a used UK one, from a reputable UK dealer..... Or maybe even a Genos 1 (budget/portability considerations). The Distance Sales thing means you could return if you're unhappy with it.
You don't say what country/continent you're considering, so you may be open to various charges, and extremely variable shipping conditions - I've some past experience in global distribution, seen a lot of damaged/ pilfered goods. Claims can take years to sort 😕 .
One other, poss minor consideration is the model age - that is to say the Sx900 could be close to the end of its probable production time?
Whatever you do, I hope you get years of pleasure from your purchase
Kind regards, steve