R9000 160MHz can not enable

Thanks for taking an interest in my problem I appreciate it! :smileyhappy:
Good to know that its not apparently a FW issue.
In other posts I have noticed that it may be a channel selection issue that prevents me from enabling it, but unlike you, I'm for some reason unable to select 2 DFS channels - If I select a non-DFS channnel as the primary, the dropdown menu for the secondary VHT80 channel only shows DFS channels, and vice versa - if a DFS is selected as a primary channel, only non-DFS channels can be selected for the secondary.
I have however not tried with those 2 specific channels, so I'll give that a go this evening - and report back! (But i suspect the same issue will occur, that I'm not able to select 2 DFS channels)

cheers
Mark

So I finally got around to mucking about with this again, and indeed it worked like a charm - thank you very much for your help!

To others having the same issues I learned the following from Schumaku's post.
-  I had to select 2 DFS channels as the primary and secondary channels.

-  You need to select channels that are at least 16 numbers, or 4 channels apart to enable 160MHz bandwidth.
-  You CAN select, like I tried at first, select channel 112 and 116 as primary and secondary, thinking this would support both 160MHz contiguous and 80+80, but THIS WILL NOT ENABLE YOU TO SELECT 160MHz bandwidth.
- Therefore selecting channel 100 as primary, means channels 100, 104, 108, 112 are used for quad streams(see under advanced tab, Advanced Home). And select channel 116 as secondary, means this uses channels 116, 120, 124, 128 (again, see this under Advanced Home). THIS ENABLES 160MHz BANDWIDTH CHANNEL SELECTION.

I hope this will help others having similar trouble. 
Once again thanks to Schumaku!