Exterior wooden door and frame (Stroud GL6)

Hi everyone, I'm on the look out for a strong wooden door (preferably in tact with frame but will consider anything offered) for an old portacabin that I am renovating. It needs to be 36" wide and up to 81" including the frame. If anyone has a door looking for a good home, please let me know. Needs to be roughly in the stroud/Cirencester area (I live between the two towns). Thank you for reading, much appreciated.