I emailed Handbox for prices of the WB-100 and got the following reply from Leszek. Price seems very reasonable to me. I've contacted Sims re UK distribution and waiting to hear back.
Hello Ian,
The price of the WB-100 is £ 800.
Transport to the UK is around £ 25-30.
Tubes prices have risen by 50-80% since the outbreak of the war in Ukraine. Most of the famous brands are produced in Russia, unfortunately.
Theoretically, I work with Sims Guitar, but the cooperation is not going well.
They have had the equipment from me for over two years and have not sold anything during that time.
All the Best
Leszek