Coincidently, I went to an Orthopedist yesterday. I've got a different set of problems to you but it's a depressingly long list. It's orthoses for me too! (I used to call them orthotics but now I stand corrected, Ha ha!)
Two things worry me about your Pod. 3/4 length orthotics are rubbish for running; you'll get a blister at the join with your normal insole if you run for any distance. Also, why wouldn't the pod examine your trainers or give you advice on what type to use? You should get the gait analysis done by the Pod not in a shop, surely? Before you splash the cash I would get some more advice.
Try this test: Stand with your feet flat on the floor and lower yourself down into a squat, trying to keep your heels in contact with the ground. If you have to lift your heels up to keep your balance before you've got all the way into the squat position, then that shows that the problems you are having are due to a lack of flexibility, and not just with the dog!
Search for calf stretches on the Internet as well as quad stretches. Good luck!
I have the 405. The main problem with the bezel is that the display can change if you knock it or it rubs against your sleeve. Also, if it is raining, and the bezel gets wet, the display can go haywire. This can be overcome by locking the bezel, but this needs both buttons to be pressed simultaneously. I often miss this and either start/stop the stopwatch or get a lap where I didn't want one. If I was buying again, I'd get the 610 for both the touchscreen and also the vibrate function. I often miss the beep when I hit the mile-point, even if I'm not wearing headphones!
I'd be careful with the 405cx that you quote the price of on Amazon, I don't think that includes the chest strap. It also doesn't mention the ANT+ stick, both of which are fairly important.
One thought for in the gym, you could just buy a replacement Polar chest strap that works with the equipment in there.