The bushes are really wobbly and the thread doesn’t seem to run right through like the battery bushes. I can’t seem to pull it or I screw it. I’d have to cut it off or is there something I’m missing? 

Unscrew them; they are threaded into the frame. The rubber has probably split  which is why they are wobbly.You will probably have to use penetrating oil as they may be rusted based on the photo and you'll need pliers to get a good grip.

The threads on the battery bushes don't go through either. A lot of us have ended up with the lower thread corroded into the gearbox. There are ways of getting the buggers out

i just recently experienced the same problem , the thread does not go right through the rubber so if you twist it too far it will tear in half as happened to me , then i got a small coal chisel and worked on moving the lower washer in the anti clockwise direction and it came loose . basically its just rusted up a bit so hard to move , try some penetrant and a small chisel and work on the lower washer to loosen it .

you can buy replacements on ebay , look under anti vibration mounts and rubber bobbins , or you can try your local car wrecker for commodore air filter box rubbers , any of the VN 3.8 models and later

A good source of moulded rubber mounts in Australia is Clark Rubber with a number of outlets around the country. If there is one nearby try them, prices are reasonable.
For those living in New Zealand the Clark Rubber equivalent is Para Rubber (subsidiary of Clark since acquisition in 1996) and they stock the same rubber products.