Okay so if I am downloading eg. a continuous steam of torrents with decent download speed (3Mbps ish) then after some time, could be 10 mins, could be half an hour or up to an hour max, then my laptop will just die network wise (windows 8.1), the wifi icon will have the warning icon and I can't do anything. Or if I'm, eg large file transfers to the server or trying to backup my laptop the the backup drive on the server, and hour into the initial backup and almost done, network dies.

I missed the "torrents" in the initial quick skim.  torrents do open a LOT of TCP connections that can overwhelm some cheap (and some more expensive) router/switches.  First thing to try would be to put a hard limit on the number of connections your torrent clients will open.

Sometimes using advanced router features such as uPNP and DNS-forwarding can cause you issues too.

Does it with file transfers too (especially during the backup of my laptop to the home server backup drive.

Ragnor: You are effectively extending the switch in the 1st TP Link link to the switch in the 2nd TP Link to the 8 port hub - so you might simply be overloading the switch port in the 1st TP Link.

If that 8 port hub is actually a hub rather than a switch you probably want to replace that with a switch and see if that fixes it. Something like the TP-Link TL-SG1008D is good bang for buck.

If that doesn't fix it I'd be tempted to try another TL-SG1008D after the 1st TP Link and before the rest of the network.

You might be onto something.... 

Dynamic: I'm wondering if some sort of network loop is being created.  If you connect 2 network cables between the same 2 network switches (or both ends of one cable into the same network switch) a network will generally grind to a halt.

Doesn't look like it from his diagram though, the fact he's using those extra routers as AP's with DHCP off connected via LAN shows he's relatively tech savy wink

Nothing is connected back into itself ;)

I've actually got a 24 port switch sitting in the server cupboard, so I might try putting that before the second TP link.