About 5 miles
Portobello Road's nearest train station is Ladbrook Grove on the Hammersmith and City line. Nearest main Line station is Paddington.
The Berks & Hants Extension Railway was part of the GWR when the line to Devizes from Hungerford was opened in 1862. Hence the distance of 85 miles shown on the Hillworth Road bridge would most likely be the distance from Paddington Station in London. The pre-motorway road distance to London was, I believe, 87 miles (presumably measured from Charing Cross) and would support a rail distance of 85 miles from Paddington.
London Bridge.
The Marks & Spence headquarters is located in London England. It is located at 35 North Wharf Road in the Waterside house which is near the Paddington Station.
To get from Paddington Station to Liverpool Street Station, you can take the London Underground. First, board the Circle Line (light blue) or Hammersmith & City Line (pink) from Paddington towards Edgware Road or Barking, respectively. Then, change at Baker Street to the Metropolitan Line (dark blue) or continue to Liverpool Street on the Circle or Hammersmith & City Line directly. The journey typically takes around 30 minutes.
Train: Earley to Reading Train: Reading to London Paddington Underground (Circle line): Paddington to Gloucester Road Underground (Piccadilly line): Gloucester Road to Hyde Park Corner
Carlisle London Road railway station ended in 1863.
Carlisle London Road railway station was created in 1836.
London Road - Brighton - railway station was created in 1877.
Braunston London Road railway station ended in 1958.
Braunston London Road railway station was created in 1895.
Wellingborough London Road railway station was created in 1845.