Thanks! It's a Hurtta padded Y harness. Hurtta is a Finnish brand which is big here too. Castor seems to like this model and it's so easy to put on - over the head and Castor lifts a front paw and we secure the buckle. I really recommend it - perhaps not the ultimate fit for bulldogs but by far the best model we've tried.
That harness looks really good, very futuristic and sleek. I got a really cheap one off aliexpress which I recommend as well,even as a spare, only cost me$ 5.71. I have a miniature bully so I got small size, but most people would need bigger I think. It's really easy to put on, you don't have to step through anything or put it over head, just put over back and fasten two snap buckles. I have a really expensive one I never use because it's too much of a pain to put on.