Books with title Eric and the Old Fossil

Eric has survived six madcap adventures so far, and now his Gran has turned up to add to the merriment. Eric ought to be safe this time. There haven’t been any presents from his mad auntie to cause mayhem and havoc, and embarrass the socks off him. His Gran has come to stay. She seems mild enough, and good-natured, but mad things happen around her, even so. Whatever can be causing it this time?