Having recently discovered that the free Xserver software I was using called X-Deep (v4.6.5) was no longer free (I wanted to find a copy for my collegue), the hunt started again for an alternative.
Luckily I discovered Xming during my google travels.
This seems to work nicely with my PuTTY sessions using X11-forwarding, so my simple needs are met (and those of my collegue).