IMO, I have seen their site and do know of their dogs. They post many of litters for sale on many of the BYB sites. I know the line of one of their stud dogs, but I would for the prices they charge look at other breeders that are know for their eithics and breeding practices. Get better quality for about the same amount of coin.
Some breeders to look into if you are looking for a UK lined pup are
Mirak Boxers - Jowhar http://www.mirakboxers.com
Kti Jensen @ global boxer - http://www.globalboxers.com
Katherine Nevis @ Minstrel Boxers http://www.minstrelboxers.com/
Alisha Mobley & Shaeward Boxers -http://shaeward.tripod.com/
Kat Medcalf - Fairview Boxers - http://www.fairviewboxer.com/
(she hasa UK girl she will be breeding in the future)
Also one of my mentors Jess Kozel - http://www.lemkoboxers.com
owns Harley who is a UK Stud and may know any planned breedings for him.
Jennifer Walker - Newcastle has UK lined dogs and may know some contact info on any upcoming UK litters in the US http://www.newcastleboxers.com
(she is also a member here).