Replacing wooden window with 2 lintel sections joined above?

[ilikewatchingtv]

Hi all - am embarking on replacing the rotten wooden window frame in my single storey kitchen. However, I have discovered that the wooden lintel which runs the length of the kitchen above 1 door and 1 large window seems to be in 2 pieces, with the join above the window. I can't see any thing joining the 2 sections of lintel - they're just butted together (from my view from the outside of the lintel).
Has anyone seen anything like this? How can I go about replacing the window?

 

[God]

Assuming there is not a great deal of weight above the timber I would use a acrow and replace as normal, sounds like its not a lintel just some kind of wall plate for the roof joists to fix to