Does it also mean existing pilots will be 'given' IR's
No,it won't. As I understand it the requirement for pilots to hold IRs comes in about 2020(?). A large number of the current pilots are due to retire by then, or shortly after. Those that are due to retire shortly after will be given grandfather rites to allow them to continue to retirement. There will be a small number of the current pilots who will be required to obtain an IR, which NPAS will foot the bill.
All newly recruited pilots will require an IR.
That's my understanding, anyway.