Regarding the Memotech MTX/FDX:

This computer was build by Memotech Ltd. in England in the early 80s.
I have this Web address: http://privat.schlund.de/groener/comp_055.htm
which worked last time I checked it (I'm writing this offline, so I
can't check it now). This should give you some idea.
----
The Web-link I added was outdated, as I found out later.

Here are some working ones:

http://www.btinternet.com/~jim.mtxinfo/mtxsite/
http://www.uta.fi/~lomise/english/mtx/
http://www.heydon.org/kevan/collection/manufacturer-memotech/mtx512.html
http://www.gondolin.org.uk/hchof/reviews/text/yc-mtx500.html
http://scorpius.spaceports.com/~cbpwr/mtx/index.htm

http://www.classicgaming.com/mtxemu/  *

* this one has an emulator for Windows! But it only emulates the basic
  machine (MTX), not the FDX extension. So it only covers the homecomputer
  thingy but not the CP/M machine.