1920 Super Six Auxiliary seats

Unknown

Hi,

I'm currently replacing the timber in the two fold down rear seats ready for upholstering and noticed the seat frames are a different size. When in the open position one seat is approx. 1 1/4" higher than the other and the curve of the upright is also slightly different. Both seat trays and  leg hinge brackets are identical. When folded the longer seat fits into the recess whilst the other sticks out. Are they meant to be different or have I ended  up with one odd seat ?  I assume the frame is cast so cutting and adding extra metal could be risky, alternatively adding extra timber in the right place does balance them out or does anyone have a spare seat frame available if I mail the exact measurements.

Many thanks

Maldwyn Jones in Wales. UK.