PCSpecialist laptops are usually easy to install Linux on. Just be sure to change the operating system to “No operating system required” to save some money by not paying for a Windows license.
Juno Computers ship theirs with Linux preinstalled.
Dell also sell theirs with the option of Ubuntu.
Hop on over to overclockers.co.uk as they sell plenty of AMD gaming laptops but I’d hit up their forums first and ask for advice or give them a call. Someone there will be able to point you towards a decent model that supports Linux well.