Anything from about 2ohm-5 ohm should work.
Use 3.3 ohm to start with but just me mindfull that resistors have a tolerance of +/-10%...which could be enough to take it below the minumum resistance required. I used 3.9 ohm on mine.
3.9 ohm was fine. 0.25w should also be fine. Hardly any voltage running through the circuit.
Im guessing ul be going to maplin?? Get a 3.9 ohm 0.25w one. 1 watt would also be fine to use.