Power your CAMERA off a USB PowerBank | GH5 | Dummy Battery - YouTube
Panasonic Lumix GH5 II Review - Amateur Photographer
In Review: Panasonic LUMIX GH5 II 20.3MP Mirrorless Micro Four Thirds Camera
Stop paying through the nose for OEM batteries - Your camera might support USB power banks
After a lot of research and not finding much that was available in the UK, I finally have come across this external battery setup to power both GH5 and monitor. More in
SHAPE J-box camera power and charger for Panasonic gh4, GH5 & GH6 - SHAPE
Amazon.com: DMW-DCC12 USB Power Cable Replace of DMW-AC8 AC Adpater kit, DMW-DCC12 DC Coupler DMW-BLF19 External Dummy Battery for PANASONIC DMC-GH3 DMC-GH4 DMC-GH3K DMC-GH4K DC-GH5 Digital Cameras : Electronics