I have booked JK code share flights by calling Spananir in the UK. If I recollect correctly this was handled by Avia Reps in Crawley and I got a hand written paper ticket! I got the number from BD reservations because Arecife wasn't a code share.

On that occasion the ticket would have cost £350 if buying separately and I think I got it for £180 in the end & that was Xmas.

I have also noticed that Opodo often list Spanir flights without a service charge, but these have been internal Spanish flights. I've just booked a business class return from Valencia to Malaga for £118 return, which I thought was pretty reasonable.

Hope that helps

Alan