Hi Eddie - your running paces are pretty fast. I had a German Shepherd/ Belgian Malinois cross (basically, a slightly more athletic German Shepherd) and she couldn't handle much below 5min km pace which is 8min miling. She could sprint much faster than me but she really didn't njoy going long. The warmer the temperatures, the more difficult it became.
It was no fun at all for the dog or for me if i ended up dragging her, so more often than not, I left her at home.
I now have a Border Collie. He's not quite a year old but the difference is incredible. He wants to run all day long, any speed you want. I've not taken him beyond 15kms yet and usually keep him below 10kms - after 18 months I think his bones will be mature enough to build up his endurance. But the thing that makes this breed so good for partnering on runs is not JUST their athleticism, it's the brain inside.
When running, it's not great for you or the dog to be linked together. They need to stop and pee and sniff and rest and sprint and investigate etc. That's how dogs have fun. They stop start all the time. Their bodies aren't designed to run at a stable pace for a prolonged period (like a husky which operates in the cold). Dog's can't sweat and the persistent repetitive running can be bad for their hips, especially when young.
So, you also want an intelligent dog who is reliable off the lead. I don't think Labradors or Poodles are famed for their applied intelligence. Put together, they just aren't so bright (happy if someone calls this prejudice or limited experience). I can call to my dog 100m away to sit if I see a mountain biker coming through the forest at speed and he will instantly sit at the SIDE of the path. Or I can make him lie down, reassuring the person approaching that he is not a threat.
If i run alongside a road, he will wait at the kerb and won't cross until instructed. I can run past him while he is sitting and he won't move until I tell him. I can't tell you what peace of mind this brings, how much more enjoyable it is to be able to trust the dog. And he's still so young. Getting a dog can be a 15-16 year commitment. So don't be tempted to buying into the first set of puppies that are conveniently available. Make sure that all of your purchase criteria are fulfilled.
I bought a sheepdog with an ISBS pedigree, not one trained for looks but for working instinct and intelligence. I think it was worth the little bit of extra time it took. Good luck.