Hans - both plants you have are Acanthus spinosus, which with A. mollis is by far and away the most commonly grown species. It is variable but your plants look just at different stages of flower development. A. mollis has very large broad leaves, hardly cut in segments - I've just taken a photo of it in our garden. This form I have has very yellow leaves in spring and doesn't seem to flower in my garden.
There are some very good smaller species - one we have flowering at the moment is A. syriacus, less than a metre high and clump forming. Others can tend to run alarmingly but I must say I like them all.
