This may help Kathron

https://www.rhs.org.uk/advice/profile?PID=195

Vacuum Cleaner fluff. Empty your vacuum cleaner into your flower bed. Works even better if you have pets. The scent of humans/predators repels them. You'll also be fertilizing the flowers - everybody wins!

Are you saying they dug them up this spring, while they were actually in leaf, Kathron? It's usual for them to dig up bulbs in autumn, usually just after you've planted them, but they don't normally dig up growing bulbs, so I'm curious about that...

One idea is to put chicken wire over the bulbs when planting and before filling in with soil/compost. I have a pair of grey squirrels in my garden and I consider them real pests.....a great pity they were ever brought over here from N America in the first place.