My dad used to put them in or on newspaper and store in a frost free place.

I don't grow dahlias, Pdb, but do grow other bulbs etc that need storing over winter. I believe that dahlia tubers need to be stored dry or just slightly moist? Why not just store them in dry compost in the cardboard box without any lining. With the minimum amaount of water that you will give them the box should not disintegrate before next summer.

Many thanks, I did read that they don't even need dry compost, so as an experiment I might put some in the newspaper. Bulba would I be ok to put a few in the same box and on top of one another with compost inbetween them?

I would think so, Pdb, as long as they aren't touching each other.
Most of the bulbs that I am 'precious' over are small South Africans that I grow in pots. After they have died down around October I repot them straight away but in completely dry compost and they sit in this until they sprout the following summer.

Having put them upside down and drained them, I just stored my in newspaper in the garage.

My Bishop of Llandaff just get placed on a tray of sand ubncovered. I was told that air circulation is good.

My father used to show dahlias and chrysanths and he always labeled the tubers, washed all the soil off them, dried them and then sprinkled them with Derris dust. (Can you still buy that.) He then placed them into shallow wooden boxes which were rather like orange boxes and stored them on top of the wardrobes in the spare bedroom. They weren't covered with anything and we didn't have central heating so they were kept very cool. He checked them from time to time for rot and as far as I can remember he just cut any rotten bits off.
I remember our garden being a mass of colour and paper bags in the summer and mud with a path down the middle in the winter. It put me off dahlias :)