Posted: 16/04/2015 at 17:42
Whereabouts do you live Emily? I'm in Norfolk and my bay tree stays outside and uncovered all winter - even in the very hard winter we had a few years ago - I just wrap the pot in bubblewrap and raise it off the ground a bit to make sure it doesn't freeze solid. However, it is in a much bigger pot than yours.
I would repot yout trees into pots at least twice the size that they're in at the moment. Use John Innes Soil based compost No 3, and add one third horticultural grit to improve drainage. Give the roots a good soaking before you repot and tease the roots out at the edges and bottom a little in case it's getting potbound.
Hopefully your bay will start to show new leaf buds and the old dead leaves will fall off - it will look very bare for a while but as long as there are buds it'll be fine.
I find that if my bay is looking a bit ropey, giving the leaves a weekly spraying with diluted seaweed fertiliser really perks it up.
This is a picture of my bay (grown from a cutting about 10 years ago) to show you the size of pot mine lives in now.
Apart from giving it plenty of root room, there's no way that'll blow over in the breeze!