New Oak Bed wood Question

[6863m]

I have installed the new oak wood bed boards and the gas tank spout did not end up under a full board. So I have to cut an opening and install a door on the deck but right where the stainless hold down strip runs. A round one will not work nearly as well as a square or rectangular shape will. But I am having trouble finding a door of that shape. I did a search but did not find anything.

Does anyone have a source or web site I can find a gas door for the bed tank, any help would be appreciated.