Perhaps this will be seen as nit-picking, if so apologies, but the BSA Catalog page above clearly says "Lee Enfield Pattern" in the title bar at top of page. Accordingly IMHO the rifles should be referred to as commercial Lee Enfield sporters, rather than Lee Speeds. Such is the rifle from the Gunbroker auction site pictured in the adjacent thread (marked "BSA Co" rather than "Lee Speed Patents" on the socket).
This takes nothing away from the quality and desirability of the various grades, and in practical terms there is no functional or aesthetic difference. Certainly when planning a modern build, the Magazine Lee Enfield Mk.I action is much easier to source than an original Lee Speed action.

Lee Speeds were from a particular historical period in British gun-making, and are essentially pre-WWI, whereas Lee Enfield sporters on ex-mil actions were offered by the trade for some time after each major war of Empire. I have a Churchill sporter on an Ishapore No.1 Mk.III made in the late '40s or early '50s, for example.

Can we assume the BSA catalog dates from between the wars?

BTW, much anticipation of JC5's contribution in this camp, too!