Hi LMD
Just a thought, have you seen those self adhesive vinyl floor tiles that you get from Wickes etc ?
They come in many different effects, marble, slate, etc etc.
They are really easy to lay, i put one down yesterday and was really impressed with them. We went for the slate effect and it looks really nice and unlike ceramic tiles is not slippy at all.
The prices range from between £3 / £5 m2.
You could just put hardboard down on your concrete floor and then peel off the backs of the tiles and stick them down. If you wanted to seal the concrete floor again Wickes, B&q sell a floor sealer that you just paint on first, i think its like a bitumen type paint, and thats it.
If you still want ceramic then ignore this but thought i would post because i am well pleased with ours.