How can I fix my Dimplex night store XL24?

I have recently moved into a house with an XL24 night store. It was going brillantly up until a couple of weeks ago. I turned it off while I was away from home on a trip to save power but it has not worked since I turned it on again. I have tried every combination on the dials but nothing works and I am wondering if changing the dials too often has somehow confused the memory. I really need some help to get it working again as it is my main form of heating. Thank you