In the UK the following frequencies to be used:
For the simplex hotspots:
Option 1: 438.800 MHz (more common)
Option 2: 434.000MHz (less common)
For the duplex hotspots:
Hotspot TX: 438.800 MHz (= personal radio RX)
Hotspot RX: 434.000 MHz (=personal radio TX)
If you use just one hotspot you can set up SSID 23xxxxx (7 digits), but even with one hotsport the good practice is to set up SSID 23xxxxx01 (9 digits). Each extra hotspot will be called 01, 03, 04.
Using 01 ID will help to prevent making loops in the network.
PS. Apparently if you set up any frequency between 435.000 and 438.000 the firmware will NOT let transmit anything to protect the amateur satellite band.