I think we know too little about the various figures to give an accurate estimate.
We dont know what your student loan repayments are, nor your pension contributions.
Suggest you just wait till you get your first pay slip (though even that figure can change if you tax code changes over the next couple of months - they may put you on an emergency tax code at first. Note there is only one more month till the end of this tax year so you may even get some money back at a later date).
However whatever you get, it wont be enough to live on :-)