I think one of your problems might be here;
I've kept up the watering.
They don't need a lot of water, particularly if they are not growing to use it up.
Note; growth generally goes with temperature e.g.
Warmth = good growth
Cold = minimal growth.
My suggestion is feel the weight of the container now, then periodically test the weight again. If the container is considerably lighter then water if not don't water.
If you think the compost is too wet move the plants into compost that is the damp side of dry, although you might be too late if they are saturated.
Forget the fleece and the bottle they are perfectly hardy and just leave it to the elements to fetch them along.
Lastly just be patient, more plants are lost by human interferance than are by the weather.