I have had a nice chelsea bun at the Brick street bakery at the distillery. It was quite delicious, but I didint ask them where it was sourced ( I dont think they bake onsite).
Also, maybe you can give Bridges British Bakery a call and inquire.
A restaurant called Sierra Grill (at Bayview Village) makes delicious and fresh Chelsea buns. Too bad the rest of their food is bloody gross. They have a huge salad bar, which I actually think is fairly decent (although I’m sure many others would take issue with this), but stay away from their regular menu -- just horrible.
The Chelsea buns however were great and always coming out fresh, placed at the salad bar.
Haven’t been in around 4 years, but that is how I remember things there. Who knows if they are still good... can’t say.
I also saw what looked to be yummy Chelsea buns at Summerhill Market, wrapped up. Haven’t actually tried them, but they sure did look good.