For the railings, I think I'd prefer the focal point deeper into the frame. Focusing on the foremost point doesn't pull me into the image.

Those watch depths are based on static pressure, equated to depth. If something can sit in a pressure chamber full of water at 5 bar, an equivalent depth will be stated.
If you actually plan to use the item in the water, then movement etc. Can be a big factor. Swishing around a 20m water resistant watch in the bath will probably cause it to leak. In my experience, swimming with a waterproof camera can have the same effect, lost an olympus "tough" that way.
If you really want true "waterproofness" you have to pay for a good housing. 10m waterproof cameras are fine for splashing in the pool, but they won't last, and won't suffer too much exuberance.

I did it last week, online, and it works fine.
The only confusing thing is that you need to type in your user id on the page before the one that asks you to select the pentax user discount. The order process is; fill out some details, next, fill out more details, next, etc...

If you find yourself having to use those fast lenses wide open all the time, a k5 would give you a few more stops to play with. That would give you some more creative control.

I bought one of those grips, and it's now permanently attached..... to the cupboard under my television.
In a word, it's horrible. It works but it feels so cheap and nasty, it makes me not want to use the camera when it's fitted.

I had a grip on my K200d, but don't seem to feel the need on the K5. I think the larger grip makes it easier to hold in portrait anyway.

As already said, save the money and buy a spare battery instead.

Low tide is very low at the moment. You could get yourself onto the Thames foreshore, that could make for some interesting photos in their own right, with the old exposed brick and wood foundations. Getting those things into shot with new modern buildings would make for good contrast.
The area opposite the tower of London might be a good start.

Not a comment on the model, but I think the shot may have been better with just the bike.
From a mechanical perspective the chain and trailing arm can make for a very interesting composition.

The camera mounted option fits with my lazy arsedness.
Perhaps the k3 will support Bluetooth options. I use a very good Bluetooth gps dongle (gets a signal while in my pocket or bag) when I'm hiking or skiing.
Conversion technology is good, but if I'm not outside, then I know where I was anyway so perhaps not so useful.
I am looking forward to seeing exactly where I was while diving though, at least before I got under the water anyway.

Woohoo, ordered. I'll let you know how it performs.

If you've already got a router at home this might be useful. No worries about speed, or power. You can add as many as you like too.