Canadian No.7 .22 caliber lightweight sporting rifle

[stencollector]

It is a Canadian Long Branch No.7 Mk1 .22 rimfire rifle from the first production run receiver markings, (1Lxxx).

Are you saying this number is on this receiver or on the bolt handle? Anything 1L with 3 digits would fall into the mid 45 range of serial numbers, where your receiver is marked as a 1944. As a general rule of thumb, the break point is somewhere around the 0L7000 range, although of course with Enfields you never say "always".