Well, I think the fix for me (seemingly) was overriding the networks on my phone by manually adding them.
I opened my wifi settings and 'forgot' the current (2.4 GHz) network. Then, even though the phone picked it up again as it could see it, I manually added the 2.4GHz network again via the 'other' button and manually typing in the SSID, security type - pressed ok, then input the password when requested.
What threw me though was that I didn't see an instant increase in speed. I tried downloading a previously bought 10MB app from the app store and it was just as sluggish - hence I wrote the 'fix' off as another fake.
I even did a hard reset after applying the settings, and again, tried downloading the app and it was still sluggish.
The following day I got back from my run and noticed there were app updates available. To my surprise I noticed they downloaded very quickly. The only difference was that I had no cover on my phone as I had just taken it out of my Belkin arm band... I was a little concerned for a couple of minutes that my regular phone cover had been the issue all along, so again, downloaded an app (the same one I always tried with) with the phone cover off and the DL speed was great.
Next test - DL with same app again with the cover back on. So deleted the app, case back on the phone, DL the app again and the speed was fine.
Next test, my 5GHz channel which I had not touched. DL the app again on the 5GHz channel and it was incredibly slow once more. So, I did the same as with the 2.4GHz channel and manually entered the settings. This time though the speed increase was instant.
I'm still not
entirely sure if this was the
only fix that made the difference. I have made quite a few adjustments back end to the phone and the network. The wifi reception on the phone is still not amazing, but all speeds across the board are very quick now.
Basically on the router IPv6 is still on, my QoS is off and I've manually set the phone to the network. I think they are the key things for my success.
Good Luck.
