You should also try all of the Evans stores (see their website, they're not all on the map yet - actually you could try them first, as they can probably tell you stock levels across the chain). I'd be stunned if there wasn't a rear, yellow, fixed/free Aerorage in the whole of London...
Off the top of my head, no idea. Have you tried actually phoning some shops? Mattty made a list, most if not all of the entries have phone numbers:
http://tinyurl.com/ldnbikeshops
You should also try all of the Evans stores (see their website, they're not all on the map yet - actually you could try them first, as they can probably tell you stock levels across the chain). I'd be stunned if there wasn't a rear, yellow, fixed/free Aerorage in the whole of London...
EDIT: http://www.londonfgss.com/post553816-114.html