As the K had the better "IMO" coil spring clutch so from the pics you posted i,d say its an 1100L motor ...
Normal 2nd and 5th carnage ........The Gears on later M , N models had a better undercut on the gears ...
You can mix and match gear,s from all the 1127 & 1157 motors "well i have" i think the water boilers use the same box as well
It's worth checking on robinsons site as the gears sometimes pop up on sale...and i've bought good complete gearbox,s of ebog for not much $$