Leigh,
The ghosted-out parts of sprue D on the instructions are the V2500 parts.

1. The rear fans (D38) sit in the groove of the engine core halves (D4 & D5)
2. The front fan (D42) mounts onto the assembled engine core.
3. The engine is then mounted inside the nacelle halves (D31/D32 & D21/D22) at the notches.
4. The engine intake rings (D11/D12) then mount onto the front of the assembled nacelle.
Cheers!