Depends what you mean by 'storage' - a refinery I worked at has bulk LPG storage in huge metal spheres and had sales contracts with a large Calor depot near by (also with bulk storage prior to road tanker and cylinder filling).
Depending on the type of crude oil refining plant, there will be a continuous propane stream produced as part of an integrated refinery, such as from a catalytic cracking plant.
Unfortunately for the UK, the oil majors have felt that there has been too much refining capacity in Europe for the last 10 years or so and combined with a free market have disposed of their refinery assets to other operators (Except Esso at Fawley, but they don't directly operate any north-sea assets) and with the demise of the Cold-War, there is little strategic guidance from Government.
A couple of oil companies specialise in ocean going LPG tankers from Africa / Middle East.
Europe and Norway have bi-directional interconnection with the UK, but in recent years that tends to flow as UK import and again is 'free market' trading.
A few years ago a new Norwegian connection came online to the UK and sent bulk gas prices negative (less than £0 - meaning producers / shippers had to pay to convey to ship their gas through the system) on a day to day basis until forward capacity estimates were reconciled.
On a north-sea gas production platform, an estimate of production is made for each hour of the day a couple of days in advance on a bulletin board for advance sale, with adjustment made for any process disturbances and shutdowns.
One of the interconnectors (for sales quality natural gas) has its own public website where transmission live and historical figures can be found...
http://www.interconnector.com