Squirrels 3 - Grumpy-grandma 4

Almost two weeks ago I planted some sunflower seeds in the little seed trays with six cells in each one. I managed to plant up three trays and left them on the gravel path just under the wall of the raised bed. I didn't think that Squidge would bother to try to bury his peanuts in them, but how wrong can you be?
Just as the first signs of green seedling leaves were showing in one or two of the cells, he decided to empty a couple of them out to bury his peanuts. I went out and replaced the compost with fingers crossed that none of the seedlings would suffer and placed some strips of wood over the trays to stop him doing any further damage. Wrong again! Within twenty four hours he had removed the wooden strips and emptied out another couple of cells.
Now I love to watch the squirrels when they visit the garden and they don't really do too much damage so I don't mind them burying their nuts in with my plants, but I was really looking forward to the sunflowers because I have never grown them here. Again, I replaced the compost and disturbed seedlings and this time I put the trays inside a large plastic bag which I pulled up into a tent shape and weighted down the side with a couple of lumps of brick. That would stop him!
Well it did to a certain extent but he kept on jumping on the tent yesterday and I said to Eden I would have to find a way to stop him from spoiling the sunflowers now that they are growing. She just found the whole thing hilarious especially when I went out there today and carefully propped a couple of kitchen towel tubes in between the trays inside the plastic bag. Eden is convinced tat this won't stop him but he never made any attempt to go near them this evening. Or was that because I was watching him?
Squidge will have to learn that he can't outwit an old bird like me!