Sounds like a crude attempt to constructively dismiss you, get an employment lawyer on it, there are plenty about. First you need to clarify if your previous job has been made redundant. You also need to ascertain the reason for demotion, it can’t just be financial.
I’m often on the other side of the coin, and I know the law doesn’t allow what is happening to you, if it had we’d have done it recently, to try and downsize.
Don’t put your faith in forums, get some proper advice, were you permitted a witness at your redundancy hearing? I did question this on the other thread, in these cases the devil is in the detail and the procedure and how it is followed.