The body (action) IS the rifle in the Commonwealth system. Everything else is replaceable.
Prior to WW1 the 'master component' to which everything else was numbered was the barrel, this was changed and even in the WW1 instructions the 'body' was the master component (see para 18 in the instructions to Armourers for No1 Mk3 rifles)
Mine are not the best, but they are not too bad. I can think of lots of Enfields I'd rather have but instead of constantly striving for more, sometimes it's good to be satisfied with what one has...