Yes, those are the 3 channels that don't overlap, but you are in the UK,
so you have more choices. In practice, it is hard to "own" 1, 6, and 11
in the US because everyone else knows they don't overlap. ;-)

Now moving around is a good question. Maybe you can put your portables
on the wap in the middle of the house.

I have no idea how to do a mesh (same channel), but you might want to go
over the alt.internet.wireless and ask about that.

I know it is personal information, but just how big is this house? I
wonder if you have a issue with the house construction more than the
house size itself. Unfortunately, I don't speak UK construction, but in
the states, if you have walls with chicken wire under the plaster, good
luck with wifi. Or ICF with all that rebar and cement.

It would also help to know what clients you are using. For instance,
iphones have terrible wifi.

This is what I have:

http://www.amazon.co.uk/Buffalo-Airs...eless-N-Router
/dp/B005G9C4C2/ref=sr_1_75?s=computers&ie=UTF8&qid=1371610644&sr= 1-75

US link has more reviews:

http://www.amazon.com/BUFFALO-AirSta...it-Wireless/dp
/B005CSOE1G/ref=sr_1_1?ie=UTF8&qid=1371610893&sr=8-1&keywords=Buffalo+Airstation+G450

You can factory DD-WRT it. It also supports openwrt if you want to hack
it. Like I said before, I simply will not buy another routers that
doesn't use open source firmware. The manufacturer gets bored with it
and never patches the firmware.

I saw that rant about port forwarding. I can't speak for that complaint
since I'm not doing port forwarding. I know you lose the usb port if you
run dd-wrt.

What you might want to do is just buy one of these Buffalos and see how
far it goes.

dd-wrt forum at
http://www.dd-wrt.com/phpBB2/