Kees,
I would suggest more for the A. tardans group, I say group because this species has a wide distribution in
most of the E. Mediterranean Islands, Greece and Turkey.
To my knowledge there are four Allium Species that flower in the area in autumn:
A. tardans [distribution as above]
A. autumnale [Cyprus]
A. tardiflorum [Israel]
A. callimischon [Greece, Turkey]
the first three are very similar in appearance and hard to tell a part.
I must say that your Allium has more flowers than all the other I mentioned, was it a common characteristic of the others too?
They are all closely related to A. paniculatum [in bloom in early summer: June, July].
A. tardiflorum from Israel was treated in the past as a ssp. of A. paniculatum as well as A. dentiferum [you have mentioned].