My router is set up correctly (and securely) - I host my own web and email servers (Linux based) as well as remote backup facilities for numerous clients. There are 12 machines here 6 of which access the machine over the LAN and the other 6 devices wirelessly. The only device that has an issue is this new laptop on the 1704 card and this exhibits exactly the same issues as many others are having. This laptop has exhibited this behaviour from a factory fresh WIndows 8 installation then again with a new install of Windows 7 (from scratch - not from a Dell disk).
I've just about exhausted any "user error" from this end ...