Can anyone please tell me what this is? I am thinking its either a gila monster or a monitor, but could be completely wrong.
It is definitely not a Gila Monster, as you can see an example of below.
It would definitely help me be sure of what type of monitor it is, if you provided more information. What size the is monitor right now, where you got it from, more pictures. Anything more would be useful.
From what I can tell, it looks to me like you have a Lace Monitor. They tend to have that skinny head, compared to other lizards of that size. As well as those distinctive bands. Other monitors tend to be speckled.
Here is a picture of a young Lace Monitor for reference: