Snails can and do climb to considerable heights.

We find snails under the eaves of the garage so they do climb. I reckon they are the culprits.

Welcome to GOY. I have the same problem and it did turn out to be slugs, they've eaten the whole flower spike, little S---s.

yes id say its slugs and snails,i put plant pots with the bottoms cut off over the lupins with a strip of copper around the top of the pots.it doesn't stop all the snails but it does help
then i go out in the early evening like a mad woman and collect any others i find hiding,dispose of them however you want to.

Thanks everyone, little blighters are the bain of my life I have given up having hostas hope I won't have to add lupins to that list- will try the plant pot/copper trick (btw what a gorgeous little doggy)