Not all Lathyrus 'do' smell.
I thought it was the annual lathyrus (common sweet pea) that 'did' and the perennial lathyrus that didn't e.g. the climbers and bushes.
I could be wrong.

I think you are right Louise

Some modern varieties of annual sweet peas have no scent either - always best to choose a variety that claims to be scented.

And almost all of the heirloom varieties have excellent scent.

Do you grow them there, Tugbrethil ?

As winter annuals, Louise. We plant them October through December, and get flowers January (early types) through April. The perennial species just barely struggles through our summers.

Because of the drought conditions ?

No, more the extreme heat. Think central Australia!

whats the procedur after they have flowered i have lots of seed pods on them can u tell me what after care they need thanks

Wait until the seed pods are dry remove from plant, open pods and remove dried sweet pea seeds, place in a paper bag and store somewhere cool and dry over winter. Sow exactly as you did this year. It will take a while for the seed pods to ripen properly.