The British based independent organization has stated that the practice of stamping of the letter 'V' (to indicate a visual inspection has been carried out) after the unique identifier stamp and the relevant date, should now cease.
I understand in the United Kingdom, a scuba cylinder undergoes a visual inspection every 30 months and a hydrostatic requalification every five years.
Historically the UK cylinder testing regime for scuba tanks used to be every two years (visual) and every four years (hydraulic)—the cylinder is visually tested when it is hydraulically tested.
This is the draft standard for gas cylinders, seamless steel and seamless aluminium-alloy gas cylinders and tubes periodic inspection and testing.
The purpose of EN250:2000 was to ensure a minimum level of safe operation for 'Open Circuit Self Contained Compressed Air Diving Apparatus' down to a maximum depth of 50 metres / 164 feet.