On Fri, 1 May 2015 13:29:33 +0100, News wrote:

You say wireless is no good due to the walls - you can install
more
than one access point, you know.

Indeed, and I have at least two spare routers.

Router does not equate to Access Point. Though most domestic internet
boxes are "all in ones" containing a modem, a router, a network
switch and access point. Personally I don't like this, it's a single
point of failure at a key point of the system. And more often than
not the best place for he modem is not the best place for the Access
Point. But anyway...

4. Move the main (and only) BT socket downstairs, and move router with
it.

Not techinically legal and the [V|A]DSL signal is tiny and prone to
interference. I'd avoid runing the phone line through a relatively
electrically noisey place like a home. Keep modem on short as wire as
possible (make one up) next to the BT socket and run CAT5/ethernet
which is designed to work in noisey enviroments to a more convient
location for a small switch into which all the LAN wiring conects.

Which is best - extending the BT socket, or extending the CAT5?

Cat5 everytime.

Or does it make little practical difference to overall download speeds?

May or may not ... depends on the immediate electrical enviroment. If
you want to wring every last Mbps out of the connection one has to
take care. 5 Mbps missing from 50 is not such a big deal as 0.5 Mbps
from 3.

--
Cheers
Dave.