Hi Rob
Marylebone was a great gathering place from the 1700's.
My own family ended up there in the 1820's having come from Dublin and Somerset.
People arrived via what is now the A40 Western Avenue (Marylebone Road) which extends west to Oxford and Wales, traditionally one of the many cattle-droving routes to Smithfield market.
They also arrived via the Grand Union canal into the Paddington Basin close to Lisson Grove.
Visitors were attracted by the Pleasure Gardens, the forerunner of Regents Park.
And much later the trains arrived at Paddingon & Marylebone stations.
Have a look at the coloring of the slightly later Booths poverty maps which illustrates the class of person living there.
The parish church just opposite Baker Street station is a later, larger building after the one originaly sited in what is now Marylebone High Street became too small for the parish needs. The birth, marriage and burial registers show that the parish was processing life events on a vast scale.
For those less fortunate, the Workhouse provided what it could in times of need.
The whole area was being developed by titled families, including the Dukes of Portland and slightly further afield Dukes of Bedford.
There are loads of resources out there on the www including maps which shows how the area develops rapidly. The census figures also increase rapidly every 10 years.
Hope this helps a bit.
MB