You can order from Berlebach direct or Telescope Express in Germany. I ordered one today from First Light Optics in the UK. They have them with double clamps as a standard fitting. It came to just over $1200 AUD including DHL freight charge. I expect I may have to pay another 10% for GST before I receive it.
https://www.firstlightoptics.com/ber...q5-others.html