Seat hinge info needed ~

I'm fitting a new middle rear seat in my Truck Cab, a high back from Exmoor Trim.

However, I need to get the hinge that connects the seat base to the back...

I don't have one as the original seats were the 60/40 benches, which have different hinges.

Any ideas on where to get this particular part..? Thanks for any info!

All the best, David ~