It doesn't seem they want you, for a reason it is impossible to guess.
Nevermind, if you have clocked up 12 months continuous service, even if under several temporary contracts that have been renewed, you are likely to have accrued certain employment rights by now. Try mentioning the words 'unfair dismissal' and 'Employment Tribunal' when the subject of leaving next crops up. Probably won't get you that permanent contract but it might get you a few readies not to pursue a claim.