Just to round out the picture: Early No. 4 Mk 1 rifles had 5 grooves, LH twist. All following were LH except for a few 6 groove RH twist made in Canada post WWII. US and Canadian wartime production No. 4 Mk 1* had 2, 5, and 6 groove barrels.
All, though, had concentric Enfield rifling.
FYI, the name "Lee-Enfield" denotes the inventor and the type of rifling. The Lee-Metford was the Lee design using Metford rifling, and the Martini-Henry was a Martini design using Henry rifling.