There is plenty information on this and other Rover forums about these codes, but yes, they indicate multiple misfires, most likely ignition system triggered. I recommend starting with replacing the spark plugs and spark plug wires. I recommend wires from STI and Champion 7070 spark plugs (RC11 PYP B4).
There is also ample information online about replacing the spark plugs and wires. The wires are not as easy to change as they might have been, due to where the ignition coils are located (back of the engine).
If you don't yet have it, I recommend you download and use the DII Workshop Manual linked below. It's commonly referred to as the RAVE (Rover Automated Viewing Environment).
Good luck, and let us know how it goes for you. What year is your Discovery?