Thank you for your comments. Any one who hasn't got one should !!!! I now want a white one, a purple one etc etc.....
To answer your question sarahrm - It's potted.
I am not an expert but would guess it's at least 3 or 4 yrs old as, when I got it it was growing it's first spike (which is still there & 'frozen') & Last year it grew a new spike & flowered & this year it has grown it's third spike & blooming.
I will soon have to convert an aquarium to grow it in as it's getting to broad to fit in it's home at the moment (5L water bottle) I had to bend the latest (biggest) leaf downward to fit ..