I was lucky that I had kept the box and the amazon receipt was helpfully tucked inside it.
I'm worried now that I'm saying the wrong length of guarantee, I'm sure it was 3 years as I remember thinking that I was a very long time 
Mine stopped turning very well and eventually stopped turning altogether and smoke poured out of it. I phoned the number in the booklet and they gave me a reference number and an address to send it to and that was it.