I just picked up one of these cables at an Aldi in Derby. It is heavy and seems well made. For the price of £6 (reduced from £25) I don't think you could buy the 16Amp flex cable for that.
A quality Adventuridge 25m Caravan Extension Cable to connect caravan electrics to any UK standard 230V site hookup. With a 16A site mains plug and 16A caravan mains socket.
230V Extension Cable
Orange PVC cover
CEE plug and socket with flip top covers
Socket and plug colour: blue & white
25m mains lead in outdoor orange for connecting caravan electrics to any UK 230 volt site hookup
Mains lead consists of 16A site mains plug, 15A caravan mains socket and 25m of cable