William Pickles Hartley is probably a bit young (25 in 1871) to have a son travelling to Germany without his parents in 1873.
I think you would need to look for a family a bit older than this one.
If the family you are looking for
is from Lancashire, a possible fit in 1871 is:
62 Bottomgate, Blackburn
Robert Hartley head 40 Beerseller and Cotton Waste dealer
Margaret Hartley wife 42
Charles Hartley son 17 Cotton Weaver
William Hartley son 15
*Margaret A Hartley daur 10
Robert Hartley son 7
Hannah Marshall serv 18 General servant
All born in Blackburn
*Polly can be a pet name for Margaret, and in fact the daughter of Robert and Margaret Hartley is named Polly in later censuses.
This site:
http://www.closedpubs.co.uk/lancashire/blackburn.htmldoes not include a Heywood Arms, but there is a
Hopwood Arms, which was at 3 Bottomgate. This pub existed in 1871, and can be found with census ref: Class: RG10/Piece: 4177/ Folio: 67/ Page: 7