Is it worth applying to Manchester with these predicted grades?

It would be best if you phoned up the uni and asked them themselves

However when I was applying yo uni, I was recommended to choose one or two universities that had entry requirements that were one grade higher than my predicted, two that were the same as my predicted grades and one or two that were below my predicted grades.
This will give you a breadth of options and provide a safety net.

But it's difficult with Manchester from what you have descibed so I'm not sure. But definitely phone them up and enquire. If you really want to go there, then pick it as an option and go safe with your other choices.

Hope this helps and good luck