Dormice will wake from hibernation if the temperature warms; I've seen them in Staffordshire in January while snow was on the ground. Harsh winters are good for dormice as continual low temperatures will encourage them to remain asleep while fluctauting temperatures in a mild winter can make them wake up. It is thought that more dormice die during hibernation than due to any other factor.
Dormice eat hazelnuts on the tree and are unlikely to come to ground to feed; the best way to provide supplementry food is probably in a bird feeder. And further bad news, if you're in Chester I'm afraid that the culprit chewing your rosehips is unlikely to be dormice as there's only one known population in the county.