Last one to do. I think I have an answer but am not sure. Would one of you see what you come up with please.
24a. Agreement by a firm over one connected with The Abbey. 6 letters. O ? A S ? ?
Thanks very much Quizmonkey. I was barking up the wrong tree. I had OKASET - agreement = OK. firm = SET over one = A I was completely wrong. Thanks VERY MUCH for your help