I doubt they are worth much at all to be honest.
The aussie dollars are worth about �2, the Hong Kong dollars less than a pound and the same for the rupees. Such small amounts that you wouldn't find anyone willing to change them.
The english coins/notes are not worth a great deal either. They are not particularly old and there are plenty of them about. You could try taking them to a coin dealer but don't get your hopes up.
Can't say anything about the stamp, I've no idea.