Human ashes have the same status in law as any other kind of ash.
Is that true? Certainly not entirely true in NZ, which has a similar legal system.

My brother-in-law had to obtain an export licence to post my some of sister's ashes to the UK. They are still classified as human remains.

Here's a trick which I sadly didn't think of when mother died. We sprinkled some of sister's ashes on the grave of our father.