SVP has been around in the GTA since at least the early 2000s, perhaps since the 90s. They've had stores in Rexdale, Scarborough and one by Yorkdale for a good 20 years now. I think their website is newer. It's built on Shopify.
They specialize in heavily discounted outlet merchandise. Some of it just B-grade merchandise - when a manufacturer reaches the end of a production line, they don't run out of all input material at the same time and they'll usually use inferior substitutes and sell those in outlets. Have many friends who stopped shopping there because of bad quality. From anecdotal evidence, they've also carried fakes at various times. Their championship Raptors New Era hats were comically bad imitations for sure.
That being said, I don't think anyone in their right mind would make fake Oakley cycling jerseys, so these are probably just an outlet stock dump.
Thanks for posting OP!
The Oakley site has a size calculator. Just search for the product code and there's a tool listed there. Not sure if it's there on the mobile site or just desktop.
FYI, all the $19 jerseys are gone except for one style in limited sizes. Some bibs and premium ($40) jerseys still left.