I went to buy one from their site but the postage is almost as much as the mixer. I got a two channel tryble device off Amazon, wish I hadn’t, it’s rubbish!
I bought one of the tiny mackie mixers from denmark st in town for about £50, and they’re great quality and can be used for all sorts. http://mackie.com/products/mix-series
depending on what you’re doing, you can sometimes get by with a headphone splitter if you want something powerless and are using line level devices. Not the greatest quality but fine for occasional use.