I would suggest buying the lee collett die set for the .303.
+1
The .303 is a great round; I took mine hunting this fall, but the round itself is not necessarily the easiest to reload. Not that there's anything wrong with the round
per se, but the Lee-Enfield rifles were often made with oversize chambers, leading to grossly excess headspacing. Cases fired in such rifles (especially multiply-reloaded cases) tend to stretch a lot, sometimes with the head coming right off, leaving a nasty sleeve of brass wedged in your chamber. Have that happen just once and you'll be inventing new words on the way home.
There are things you can do to mitigate that. First off, you can get your rifle checked for excess headspace by a gunsmith. If there is excess headspace, you can sometimes swap bolt heads (which came in different lengths) to fix the problem.
Prvi Partisan brand ammo (which you will have to look for, but is available in Canada) has a rather thicker rim than commercial North American stuff, so the headspace problem is reduced. Another way is to slip an O-ring over the round, up against the rim, the first time you fire it. That holds the head tight against the bolt face, so the stretching happens in the forward part of the case, not nearly so serious.
The third one is to reuse cases in the same rifle you fired them in and neck-size only vs full-length resizing. The case is already stretched to fit the chamber, so neck sizing doesn't push it back to the 'book' size which will, on firing, cause more stretching. This is where redryder's suggestion comes in.
Lastly, monitor your cases for how many times you reload them. When you find the average 'fail' level, toss them all just short of that.
Good luck.