RT-AC5300 2nd 5ghz channel not available

I just set up my 5300, everything is fine and working as it should. But I cannot use the 2nd 5ghz band as the channels available start at 100 up to a maximum of 140 @ 20mhz, 100-136 @40mhz.
As I am in UK most of my stuff doesnt see those bands and my AC68-PCE card in my PC doesnt. I have tried the latest Merlin and Asus firmware. Is there anything I can do to solve the issue?