Decendents of Richard/ George Duke of Clarance

I have had problems keeping up to date, due to the number of posts etc.  Can someone explain somethings to me if possible I know we have very experienced members here:

Who are these people claiming descent from Richard who want him buried in York, and have they provided any finance in trying to find him?

Why was Clarence buried in Tewkesbury? and not with his father and brother

Thanks in advance