Lilium martagon is just as prone to lily beetle attack as the Asian lilies I'm afraid...

they are sadly, but due to the tall stems and wide spacing of the leaves they are easier to spot and pick off. The ones I have in a shadier part of the garden don't seem to be as badly affected though.

I have found the beetles are especially fond of the martagon lilies. Also, they don't put on much of a display the first year, taking twelve months to "settle in"

Neem oil & Spinosad are somewhat effective against the beetle but it's a task to keep up with the correct application.

Thanks, Bathgate but after the other answers I think I'm going off the idea, sadly, as lily beetle is such a pest and I already have it in the garden.
Thanks everyone for these replies.
Any ideas of what I could use instead, apart from gladioli, to rise tall and stately above hardy geraniums?

Sidalcea gets to a decent height and has pretty hollyhock like flowers. Delphiniums Ornithogalum saundersiae are also possibles.

Veronicastrums?

Verbena bonariensis? It'll be in flower for a lot longer than martagon lilies...

Thanks for the suggestions. I have quite few self seeded verbena bonariensis around the garden, but it hadn't occurred to me so far, to use it in that way. Sidalcea sounds nice and veronicastrums I am just about to look up! I will probably go for the v b as I already have some. Thank you all for your help

I can send you a small piece of the sidalcea 'party girl' if you want to try it. send me a pm if you do.