INFORMATION:

Portishead is situated on the north Somerset coast with its own small port facility. It sits next door to Avonmouth docks and in WW2 a very big petrochemical works, one of the major petrol works in the south. On the coast to the west of Portishead is a fuel depot. Portishead Wikipidia.

OS Ref: St441750
You can use the Ordnance Survey 'Get a Map' and follow the instructions. Copy and paste the map reference.