You need one of two things to power it from batteries.
First, you can have the red battery module; if it’s not available from anyone in the UK directly, you might try Mouser who I think stock GHI gear, or you can buy one from GHI direct (I know, freight sucks… I live in Australia!)
Second, you can use a standard battery holder power source (enough batteries of some size, giving 6v or more at full charge) and have that feed into a red USB/Power module (the GHI USB DP module or similar). That could be two 18650 LiPo batteries, or 4x AA, AAA, C or D size batteries; you just need the right size connector to plug into your DP module. It could even be a remote control battery pack of over 6v if you wanted.
You also need to remember that depending on the battery capacity and what other modules you have connected, you’ll get varied run-time of it.
and others as well as the UC Battery 4xAA Module but as you can see there is a theme going on as typically I get things that generate power which is accessed via a usb connection which just makes stuff easier. Now when I have motors etc that eat power sources then I tend to go with batteries but it feels so Neanderthal. If someone could just make a fusion module then I’d be really happy