This is how mine were sheltered, with bubble wrap.
Bambi, these are aqua dulce broad beans, they are for sowing in October and live through the winter but some protection against freezing east winds (in Holland) helps them. Last year mine had no protection and were a bit slower than this year.
Two reasons I like to grow the autumn sowing type of broad beans.
Harvest before the black lice get really bad and have the space available early enough for growing more summer things.