] Gracechurch Street, where the Gardiners live is in Cheapside (in the outskirts if I understand correctly) just follow north the London Bridge and that is Gracechurch Street.

Gracechurch Street and Cheapside are very close to one another. Here's the relevant section from a current map of London. I've put red arrows pointing to Gracechurch Street, Cheapside and East Cheap. As you can see, they either intersect or are within easy walking distance of one another and of the Bank of England, at Threadneedle Street.

Because of its business associations, this was not considered an acceptable place for those with pretentions to gentility to be living. Darcy considered that the Bennet sisters having an uncle living near Cheapside would "materially lessen their chance of marrying men of any consideration in the world." And Lizzy wryly remarks to her Aunt Gardiner that althoughMr Darcy may perhaps have heard of such a place as Gracechurch Street...he would hardly think a month's ablution enough to cleanse him from its impurities, were he once to enter it."