Thanks to many boating friends who suggested ways of retrieving lost phones and other precious things from bilges and other places I might float - test them (after the phone bilge float test incident last weekend) . A litter grabber from a pound shop looks like a winning option! Indeed fellow Oyster owners report that they are standard equipment. Here I am practising with it at home. A child's fishing net sounds like a good thing to carry too.
My daughter suggested I fit an auto inflating key buoy to it too.