hello marmite, welcome to the team!
congrats on your decision to take some of that weight of, i personally think (and have experienced) that swimming is a great way to get moving and burning lots of calories.
starting on the channel swim would be great because someone has just "jumped in" there this week, so you would have someone to challenge you for distance, which is always nicer than being alone on a challenge. she has a little head start but you already got 2K you can track too!
we don't have a timed distance swim, i don't know how many of us swim for speed (i'm quite lame compared to you since i swim breaststroke). you can just start a new challenge thread and explain the rules or the idea and i will send an email to all team members telling them about it and to join in if they're in for the challenge!
thank you for bringing up a new idea - now enjoy your time in the water and on the team!
"Our way is not soft grass, it's a mountain path with lots of rocks. but it goes upward, forward, toward the sun." *Dr. Ruth Westheimer