Considering a single SXT is priced at $89 selling a pair for £249 is quite a markup for just the reseller’s name.
Avoid! 
what?
Oops - forgot to post the link:
let’s not use this forum for calling names, maybe it’s a mistake on the website, or maybe those people are happy with their pricing scheme. just buy elsewhere.
Send them an email. Likeky it should have been 1xx instead of 2xx in the price.