Aye, some cats are just nuisances. I had a female was horrid to her brother, who only ever loved her and looked out for her. When he was shot dead she did of course miss him. When I got a new kitten, he just ragged on and on at the incumbent, who agreed that she should have appreciated her own brother when she had him...
So long as Polly can get away from the little pest, she'll be fine. Poor Toby - how much longer is he supposedly on 'cage rest'?