Hi, my DD has refused to leave her cot till now (3yo) but she seems to be enthusiastic about a started bed at last; I'm looking for a mattress (140x70) that will last 4-5 years max (she's a tiny lightweight) then I will need a proper single bed. Has anyone one of those "natural" mattresses such as the little green sheep one - just coir and wool, no springs? I'm wary of all the chemicals used in normal mattresses and am looking for something more natural but they're very expensive. Any recommendation / thought welcome, there are so many out there, bamboo, coir+springs etc etc. Thanks!