Old - Great shot, lovely composition, great clarity in the sky and love the reflections.
Metal - Again lovely sharp shot, the colour of the metal roof contrast really well with the clear blue sky.
Captive - Like the idea behind this, I hate the tube, luckily only ever been to London a few times over the last 25 years but certainly feels like your a captive in one of them. Great use of mono too.
Miniature - Interesting shot, great to remember to get some background interest there with the passer by. At first I thought the focus was a little off on the nearest statuette but looking at your flickr version shows it's spot on.