If they were advertised for say £250 on the basis that if they were being collected then I could understand that they might want a bit more if you're asking them to package them in a very specific way (I'm only going by the diagram on the last page, to me that looks like it could be a ball ache to secure two seats together in that arrangement whilst being secure enough they aren't damaged/separated in international transit) as opposed to just quickly strapped down top a pallet which is probably a 5 minute job tops. £50/60 seems a bit steep though it has to be said. Then again you don't know how much their time is worth to them - it might be that it's really not ideal for them to arrange packing them up and sending them out, but they're just trying to give you an option rather than outright saying no... Without the other party present to give their reasoning you can't really say definitively imo.
Just my two pence
