Be careful, Youri. I had a goanna that fitted through a hole in chicken wire kill a young standard size New Hampshire cockerel. They're the chook keeper's worst enemy because apart from getting addicted to eggs (and being incredibly sneaky so you rarely even find out what's taking eggs) they teach the chooks to break eggs and eat contents, so you end up with hopeless egg-eaters.
The only way to stop goannas is to have an electric wire. Or have a fully enclosed and roofed pen (not bird netting but wire mesh, thick wire, not bird mesh). A 10 foot high fence is nothing to them.
Catching and relocating is only useful if they're not common in your area. But it's worth a try. They're very wily, but if you trap one in the pen, you may be able to herd it into a smaller cage using a couple of rakes and get a parent to drive it somewhere over 5km away. Just don't let a scared goanna use you as a tree!
Tractors are another possible way of deterring goannas. A movable house tends to confuse them.
That's all I know, but I learned it all after a long war with the beautiful but irritating things!