neither Medicare nor maxi - above 1.60 unsustainable.

The dress is too short and might be able to fulfill its purpose at a size of less than 1.60. For larger women the length reminiscent of the skirt hems after the war: neither Medicare nor maxi and therefore actually unsustainable.
The draped top of the dress is sewn to a close second layer, which sits like a lining inside the body so that the height of the gum is not like other garments of this type can be varied.
From the comments it can be deduced that the length may well be very different depending on the broadcast. Everyone must therefore decide for themselves whether the risk should be addressed to stand with a too short dress there.