Hi Peter, on mine, one end of the rubber inserts has a slightly wider rubber section that holds them in place in a similar type of fashion to the old stainless steel clip you mentioned. If you grab that end carefully with some pliers you should be able to remove the insert, steel & all, & slide them all the way out. You can actually remove the blade head from the arm by way of a plastic clip/catch set up & slide back down towards the mounting point of the arm if you want to remove the whole head to make it a bit easier than bending over the bonnet.
Good luck
G.