Perforce sync error when using Switchboard

hey guys im struggling to use switchboard to sync perforce - I’m fairly sure i’ve set the clients up properly in the config, as you can see I am able to get the CL on each machine when I first connect to Switchboard Listener

But am getting the following errors when trying to sync:

LogSwitchboard: Display: Output:
Traceback (most recent call last):
  File "C:\Program Files\Epic Games\UE_5.5\Engine\Plugins\VirtualProduction\Switchboard\Source\Switchboard\sbl_helper.py", line 1133, in <module>
    sys.exit(main())
             ^^^^^^
  File "C:\Program Files\Epic Games\UE_5.5\Engine\Plugins\VirtualProduction\Switchboard\Source\Switchboard\sbl_helper.py", line 1127, in main
    result = app.run()
             ^^^^^^^^^
  File "C:\Program Files\Epic Games\UE_5.5\Engine\Plugins\VirtualProduction\Switchboard\Source\Switchboard\sbl_helper.py", line 602, in run
    return self.run_sync(options)
           ^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Program Files\Epic Games\UE_5.5\Engine\Plugins\VirtualProduction\Switchboard\Source\Switchboard\sbl_helper.py", line 611, in run_sync
    self.check_sync_options(options)
  File "C:\Program Files\Epic Games\UE_5.5\Engine\Plugins\VirtualProduction\Switchboard\Source\Switchboard\sbl_helper.py", line 1014, in check_sync_options
    self.p4clientspec = p4_utils.p4_get_client(self.p4client,
                        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Program Files\Epic Games\UE_5.5\Engine\Plugins\VirtualProduction\Switchboard\Source\Switchboard\switchboard\p4_utils.py", line 271, in p4_get_client
    records = p4_get_decoded_records('client', ['-o', get_client_name],
              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Program Files\Epic Games\UE_5.5\Engine\Plugins\VirtualProduction\Switchboard\Source\Switchboard\switchboard\p4_utils.py", line 256, in p4_get_decoded_records
    records = p4_get_records(
              ^^^^^^^^^^^^^^^
  File "C:\Program Files\Epic Games\UE_5.5\Engine\Plugins\VirtualProduction\Switchboard\Source\Switchboard\switchboard\p4_utils.py", line 223, in p4_get_records
    proc = p4(cmd, opts, global_opts=global_opts, user=user, client=client)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Program Files\Epic Games\UE_5.5\Engine\Plugins\VirtualProduction\Switchboard\Source\Switchboard\switchboard\p4_utils.py", line 207, in p4
    return subprocess.Popen(args, stdout=subprocess.PIPE,
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Program Files\Epic Games\UE_5.5\Engine\Binaries\ThirdParty\Python3\Win64\Lib\subprocess.py", line 1026, in __init__
    self._execute_child(args, executable, preexec_fn, close_fds,
  File "C:\Program Files\Epic Games\UE_5.5\Engine\Binaries\ThirdParty\Python3\Win64\Lib\subprocess.py", line 1462, in _execute_child
    args = list2cmdline(args)
           ^^^^^^^^^^^^^^^^^^
  File "C:\Program Files\Epic Games\UE_5.5\Engine\Binaries\ThirdParty\Python3\Win64\Lib\subprocess.py", line 608, in list2cmdline
    for arg in map(os.fsdecode, seq):
  File "<frozen os>", line 824, in fsdecode
TypeError: expected str, bytes or os.PathLike object, not NoneType

I have tried running switchboard/listener processes as admin, setting clobber on workspaces, checked p4 set, p4 client etc. but no luck.

has anyone come across this? using UE5.5.4 / Switchboard5.5