I would say go with what you can get rather than trying to get something you might not be able to. Must be a local poultry or fur and feather auction in your area - normally these are much cheaper than breeders.
As has been mentioned, Rhode Island Reds, Marrans, Light Sussex and hybrids are what people go for with good reason - at my local auction I would be looking to pay £15 give or take for a couple of hens and a cockerel they can breed with, perhaps the same for three hens, but they normally come hens and a cock - the auction keep the cockerels if people do not want them and eat them. If I could not keep a cockerel, I would take it home and eat it myself.
http://www.preloved.co.uk/adverts/show/1...-sale.html
http://www.pets4homes.co.uk/classifieds/...escription
I would get a mix of different stuff. One or two of them and a couple of those and so on.
And while you might not be up for keeping a cockerel, I live in a town on the edge of Tyneside - would definatly be classed as urban, although 2 miles away is the country side - and I keep 10 cockerels in the garden. Bought young ones at the auction, were sold as hens, paid so little worth raising them myself to eat. I do not let them out early on, at least until 0830, will be later when it is still dark at that time. By the time I have let them out, they have done all the cock a doodle dooing they want. Decent housing, covered in felt, absorbs most of the noise. You have to be within 30 foot to even notice it. You could keep them outside a double glazed window and never know. Or maybe its because I have double glazing and they are not next to it I do not hear them, but I have asked all of the neighbours, none of them have heard cock a doodle doos.