well, the plastic extruded sprue that these are made from in hexagonal profile can be cut with a sharp knife to the thickness you would have required by making a simple jig so that each and every bolt head would have been exactly the same thickness...........it would have probably taken around two hours to make all 1500 dummy bolt heads.........( saving you "solicitors" type fees of 240 quid an hour at the rate you paid for yours....then simply stick them on rows of inverted masking tape......spray with silver and then glue to your decks and cabin of the Severn
they would look just as effective as the lot for the price you paid, a fraction of the cost, and you could sail your lifeboat in salt water without fear of them going rusty, because even nickel silver at that size will rust unsightly in salt water.
neil.