Thanks for the replies, and sorry for the lack of detail in my original post
This is my guitar:
A G2 flying V (made by Stagg apparantly). A really cheap guitar, and I wish the balance had been the only problem with it. But buying a cheap one and attempting to upgrade is certainly teaching me a lot about guitars.
You can see where the straps are fixed at the moment - one on the top near the neck on the left, and one on the very bottom left.
So having ruled out moving the strap pin to the neck, I'm interested in the other options. Replacing the tuners for lighter ones, not too sure where I'd get lighter ones from. A site I've been looking at has lots of tuners but does not give any details about their weight.
I'd like a more permenant solution than simply adding weight to the strap - fixing a metal plate on the back sounds like the best idea and a more permenant solution. Unfortunately I don't have anything like that lying around. Is there anywhere I could buy something like that from?