Spec me a new Wireless AC Router

I have recently noticed the 5Ghz wifi strength and speed has deteriorated at home. Up until a month ago, it was wall to wall strong and fast 300mbps+ using my BT Smart Hub 6.

As the Smart Hub has been annoyingly rebooting every 14 days, I decided to go out and buy a TP-Link Archer VR400, in the hope I could switch 5Ghz channels as using wifi analyser on my phone, channel 42 which my Smart Hub and the TP-Link use there are 4 other AP's - very close and strong. I think this is the issue. The TP-Link only goes up to CH 48, I was hoping for something in the 100's. I am only connecting at 6mbps upstairs on 5Ghz and the router is directly below.,

So, i'm looking to try another router. I have a HG612 modem, but would prefer an all in one solution if possible.

I'll be looking to buy second hand off an online auction site. Budget is around £70.

I was looking at the Linksys WRT1900 or an Asus RT-AC68u?

Can highly recommend the Fritz!Box 7530

It can run 5GHz AC on channels in the 100s (doing this myself as there is no one in my locality doing the same, so no overlap with the neighbours).

It has a built in modem so you can use it as an all in one, but also a WAN port so you can use your own modem if you wish (I'm using a HG612 with it, as it allowed me to monitor detailed stats of my connection).

They are currently around £100 new on eBay, though are going for between £40-£80 second hand.

I wouldn't get the ASUS as an all-in-one, their internal modems have a bad reputation.

Big fan of the ASUS and have owned the AC68U and it works well. I've upgraded for faster CPU to the AC88U.