Niggles: Nope. I have a ton of GOG games already installed on my PC and in all honesty, id rather not install galaxy and screw up the installs
It didn't screw anything up for me when I installed it. It detected most of the games I had installed and when I told it to scan for other games it found those. When I install a new game (I install via the standalone non-Galaxy installers), it picks it up right away.
Niggles: (where is development of Galaxy as it stands at the moment ? - can i download the installers to where i want?
Yeah, you just need to go into Galaxy's settings and point it to wherever you want to DL the installers.
Niggles: , can i install games to whichever hard drive partition i want to?.
Yep. Again, just tell it in Settings.
Niggles: does galaxy keep a separate copy of the installer ?)
If you go to MORE and choose to download backups and goodies, yes.
It's not perfect, but it's reasonably robust. I tried it three separate times over several months when it was first released and it didn't work for me at all (on Win7 64 bit). Now it seems to work fine for me (Win10 64 bit). There's certainly no compelling need to use it, but I wanted to test it out to get a feel for how it's coming along and I've just continued to use it for the nonce and don't have too many complaints about it. YMMV.
NoNewTaleToTell: I installed a version of it when it first released in its alpha form, when GOG was giving Alien vs Predator away to help stress test it. It didn't last very long on my hard drive and I'll probably never reinstall it. I'll keep necromancing the remains of the GOG Downloader as long as possible and then switch to browser downloads when necessary.
Same here and tried it a couple more times over the next several months. It was woeful. But I tried it again this past fall and it's much, much better. If you're inclined, I'd say give it another shot. If it's anathema to you, then there's certainly no need for you to use it.