Wingman,
B2N2 is spot on, you do not need to undertake your PPL again as you hold an ICAO PPL. Ask them face-to-face why they belive you need to retake and watch them squirm
You can add an IR to a foreign based PPL. If you undertake your CPL it is a stand alone licence and your PPL has no bearing whatsoever on it.
they are just trying to exract money from you.
J.