So I bought one of these recently (ANVIL FORGE BURNER - ships with UK compatible propane adapter) - rated as 11.4kw (39,000 BTU/hr) on the website (yet seemingly 21kw in the URL slug)
And on the manufacturer's website, it's listed as 80,000 BTU/hr (Anvil Forge™ Burner | Forge Your Next Brew!)...
