Parts ID Mossie Or Wellington

Can anyone help with the ID on this part. I haven’t been able to find any stamps or part numbers but suspect they will be covered by the wooden attachments
The metal plate measures 43 by 5 inches and is quite thick. Its obviously bolted or attached to 2 wooden pieces. The holes for attachment are counter sunk which leads me to think that its an external part, possibly bomb bay ??
It was found along with some other Mossie parts and Wellington parts