Ivor was a member of the Kensington Firm until Margot killed him.
Ivor was attending the first US meeting of the Kensington Firm, run by the newly-in-charge Margot. However, he wasn't paying attention to her and was using his phone. When his phone rang, he stood up to answer it, but Margot shot him in cold blood before he could talk.
He worked for the Kensington Firm until his death.