Connect two boards together after removing Screw Terminals
Phoenix contact manufactures board-to-board connectors that use 3.5mm pitch, they're actually quite common. It's a bit bulkier than the header strip, but it will work, take a look at this:

Phoenix Contact - Product list - Headers (press in)

Also, check Farnell and Mouser if they are available in your country, you'll definitely find something that suits your needs.