Check out www.defender.com
they have lewmar, port light lens, screens and interior trim rings. You just have to have one in hand to take measurements from. They are pretty good at matching up what you have to what they have.
I'm assuming you meant lewmar. Bowmar is the horizontle hatches I think. But I am wrong! Westmarine sells the Bowmar. Seems defender does not have them on the website. But call. they have an amazing stock of parts.