iPhone 5 wifi issue

Hi, I was wondering if anyone could please help me out...

When I come home my iPhone automatically connects to my wifi network and shows as having good signal. Then if I try and use it it will normally load the first page or app I try, but th second web page will load forever. No timeout page or error messages, it just won't appear.

I then have to switch phone on and off and it will start working immediately (switching WIFI on/off does not resolve the issue. I have a 4S as well and have tested using both phones when the 5 isn't working and the 4S works fine.

This is only happening on my home WIFI, my work network has no issues and once I am connected I have no further issues until I leave home and return again.

I have tried quite a few things, but now I am out of ideas.
I have a Sky Broadband router (Sagemcom F@ST2504n).
Any suggestions not on this list would be greatly appreciated.

-forget this network then re-add
-settings/general/reset/reset network settings
-changed to different WIFI channels
-tried different WIFI security settings ( WPA-PSK (Wi-Fi Protected Access Pre-Shared Key), WPA2-PSK (AES), WPA/WPA2-PSK (Mixed Mode)
-assigned static IP address to phone
-took phone to Genius Bar where they replaced it for a new one but the problem still persists.

Thanks,

Mark