Hi, Hanley P
A lot of what you say or conveying about moment of people from parish to parish also across parish boundaries, or permanent migration from one parish to another and has to take into account many factors in history. Wealth, poor, poverty, occupations, trades, apprenticeships, laws, regional uprisings, Militia, land owners as deeds , tenant farmers leases, general workers known as labourer and many other factors like parish rules and regs as poorlaw. Therefore whether Thomas Hanley was one of the very few who did migrate over 10 km or 100 miles in the extream or one of the statistics who never moved above 10 km away, if he did migrate? there could be settlement/removal/overseers relief payments records or his parish of birth records if he receive relief payments from is birth parish in another parish.
http://en.wikipedia.org/wiki/English_Poor_LawsUrban city/town life in parish's and country agricultural ural parish life, also the workforce did differ, where as its been already mentioned aforesaid on this board thread that in farming communities workers did travel across parish boarders to markets, to move livestock and travel to different farms as harvesting time as each farm got their crops in and then on to the next farm. These workers would probably would have been young single men before settling down to a married life whether that be their home parish, their future wife's parish or where the young man found his employment.
With disease rampant then with short life expectancy, people moving to cities to find better paid employment from country life, leaving the farmers to travel futher to find workers.
As said statistics & real life factors do differ and as you say with basic parish single line BMD's entries pre 1754 it is very had to prove anything.
Again in short if they were wealthy or very poor there were records but in between as people with jobs or trades the records are poor! if non existant. Cork screw thinking is really need here.