In chapter 11, JA says but all the holidays of this autumn had been given to sea-bathing for the children, and it was therefore many months since they had been seen in a regular way by their Surry connections, or seen at all by Mr. Woodhouse, who could not be induced to get so far as London...

That JA specifies that Mr Woodhouse has not seen the John Knightleys makes me think that Emma as well as Mr Knightley has. Perhaps when Miss Taylor was living with them Emma could visit her sister in London.