Spanish gas cylinder

[Fastchas]

Some years ago I lived in Spain for 6 months, in & out of a caravan on a site in Almeria. Whilst there I purchased one of the spanish style gas bottles and regulator, bringing it back to the UK some months later (rightly or wrongly).
The bottle has been used for my BBQ since then but is finally emptying. What can I do with this bottle? Can I take it to be refilled? Will someone exchange it (doubt it)? is it only any good for scrap now? Can I take it to the tip if so?
It's a medium sized one, about 2ft tall.