Slide Windows Options - RHD Driver Side

[timthemod]

My camper is a converted transporter (tin top), has windows in the passenger side sliding door and drivers side panel next to the cooker. Both Rear panels are still metal. The window on the driver side is non opening, which is not great for ventilation generally and when cooking. Most windows with sliding windows or louvers and slightly too small to fit, and the sizes all seem a bit vague. Any ideas?

Thinking on putting some sort of vent in the roof to help with this, anyone any experience of this?

Thanks for looking.