i've found halfords the best not always the cheepest but they do build the bikes up for you, and as i had my bike from another shop and had to put it together myself i put the front wheel forks on the wrong way round and kept gettin my feet stuck in the wheel when i turned and i ended up on my ass more than in the saddle, so halfords gets my thumbs up, dont get your accessories from them though there a rip off !!!
perhaps some zebra crossings would be apt for sf that way emergency stops to the rear might be avoided