Eliminating false information
Every Harrier I (defined as having a 201 sq ft metal wing) was made and test flown in the UK. None were made elswhere.
When it comes to the Harrier II (230 sq ft plastic wing) every wing and cockpit was made in the US. Every rear fuse, tailplane, engine and reaction controls was made in the UK.
Final assembly for Harrier II was in the UK for UK customers and in the US for US customers. Neither country was able to make the whole aircraft.