Compensation towards arbitrary dismissal for redundancy

Hello,

I am currently employed at a Private British School under an unlimited contract.

I was informed in March that there is not a job position for me in the next academic year and therefore I have been made redundant, however, I am to complete my contract up until August 2019.

The deputy head asked me to hand in a letter of resignation to which I refused as I am not the one who wants to leave my employment.

I was wondering due to the school making me redundant, am I entitled to 3 months additional salary once my contract is complete?

Where can I find information on this?

Thank you in advance.