H.M. Customs & Excise

Ron was an Officer of H.M. Customs & Excise http://www.hmce.gov.uk/ 1957-1965

that site has disappeared as the Dept is now HM Revenue and Customs http://www.hmrc.gov.uk/
and also disappeared is the the Department's history page http://www.hmce.gov.uk/about/ourhistory/customsrecords.htm - it had Timelinesand  links to Archives PRO etc  

Instead check http://en.wikipedia.org/wiki/Customs_and_Excise_department

The Museum http://www.liverpoolmuseums.org.uk/customs/

and The National Archives http://www.ndad.nationalarchives.gov.uk/AH/19/detail.html

Records for HM Customs officers and Excise men - they used to be separate services - are held at PRO/TNA Kew http://www.nationalarchives.gov.uk/

Most documents have the prefix CUST example - minutes of Board of Customs CUST39 
It requires a personal visit or you employ a researcher they have a list of people at the site TNA/PRO.
Try PROCAT catalogue Officers of Customs - http://www.catalogue.nationalarchives.gov.uk/

The Custom House was the HQ of HM Customs. It is the place where importers go to pay the custom duties on goods.
Usually they would use a customs agent (private company) to prepare an entry which detailed the goods and ship on which goods had been imported into the London docks. The officers at the Customs House received the monies and
checked calculations - and ensured all goods on a ship's manifest did eventually get a customs entry. Officers were located at the Docks and would check and release the goods when entry was seen. This has a good painting of the building.
http://www.spartacus.schoolnet.co.uk/LONcustom.htm

Family Tree Magazine UK in April 2004 had an excellent article on researching C&E officers.

This Port of London  site has a lot of detail on Customs in London 
 and if you are interested in The Port of London look at the other links with pictures of local offices in the Docks.