You have a silk purse hidden by a pork rind. There are a few positive things on your side. The remnant rear pad, 71L serial number and C405 number on the butt are absolute proof. You didn't win the lottery, but you did win a key to the secret clubhouse. Take a long read of the following article to understand what you have “Is my Lee Enfield sniper rifle a fake?†- Enfield-Rifles.com I would strongly recommend that you take this rifle as a long term project that cannot be rushed or compromised.
There is an extremely thin chance of ever finding that Canadianmade telescope. You will however, find modern reproduction telescopes, pads, cheekrests and fittings to rebuild this rifle to its original glory. I think your next purchase is a complete good condition 71L Long Branch rifle in order to rob it of all the essential parts, with a few careful exceptions.
However, well done! And please make this your first stop for information and advice.