I'm no framer, but I'd imagine definately spacers

Yep just stuck them to the glass, the print looks wicked in the frames, I will post pics up once there done. Cheers

Yes, the same way you took them out.

It's possible that because you've put the spacers and print in that the clips won't fit anymore because the ridge they slide into is too close to the backboard. I've had this happen on a couple of prints I've framed. If that is the case and you can't use thinner spacers, the easiest option is to tape up the back rather than use the clips.

Yes, though let me clarify.

Ideally, get some tacks or framer's points to secure the backboard and then tape it. Though, I'm guessing you probably don't have any tacks at home. Therefore, if you can get the original corners back in and then tape it, IMO that should do the job for the time being.

I've got a couple framed like that at the moment and they've been fine for the last 6 months, though I keep meaning to pick up some tacks and finish the job properly.

That's good advice CBL and saves a bit of hassle.

Though, if you want to keep the whole operation in-house, you can pick up corrie-cor or similar conservation backing from a good framing suppliers. Alternatively, an even cheaper solution is to get a sheet of acid free paper/card and stick it between the print and the habitat backboard.