For what it's worth

The TP-link M5350 is a neat device, and (once I had it configured for giffgaff ) and it worked a charm from my Android tablet and from an XP netbook.

And then I tried to connect to it from an Acer Windows 8 laptop. Misery.

The laptop found the network without problem. In the Wifi panel, it would connect OK to begin with, and then modify to "limited" status after a minute or two.

It had a compatible IP address but wouldn't ping the M5350 (let alone access its configuration page), even with Firewall off. So what was going wrong?

Changing from Channel=Auto to Channel=6 saw me able to ping - 100% success. But repeat the ping, and the address wasn't found. Changed to channel 7 - same thing.

Eventually I solved it - I switched the band to 11g only. And everything worked fine. Not sure I understand why, but hopefully this might just help someone else.

Browse to the home page of the unit (default is 192.168.0.1). Password is Admin

Under the Advanced tab:

Dial-up
Dial-up type: Auto
Profile Management
Profile List: [up to you]
Profile Name: [up to you]
APN Type: Static
APN: giffgaff.com
Username: giffgaff
Password: password
Authentication Type: Auto