No, you need 5. Live, Neutral, Earth, . Also a wire from 1 on the hive receiver to LS in the boiler and a wire from 3 on the receiver to LR on the boiler.
https://www.electricalsupplies.co.uk/5-core-flexible-cable-white-5-core-1-5mm-per-metre?gclid=CKyAoYyq6NECFQO77QodgpILdQ