Followed the instructions and all working on a Pi5
Thanks
EDIT
Took about 10 minutes for MLAT synchonized message to appear on the Stats page but it was showing as synchronized on the monitor attached to the Pi quite quickly
Location Set: 11 November 2021 1:02 PM
Location Source: User entered
Feeder Check-In: 3 minutes ago
Feeder Type: PiAware (SD Card) 10.0
Feeder Mode: Mode-S (1090 MHz)
Multilateration (MLAT): Supported / Enabled (synchronized with 158 nearby receivers)