They look quite delicate could it be the wet and the cold winds?

They look like Cupressus macrocarpa Goldcrest - Lemon Goldcrest. They are hardy but are damaged by wind and if the soil is too damp. The pots look large for the size of plant, so I am assuming the pot is getting too wet and that is causing rot. Not sure if the last 3 are salvageable, I would cut off the brown bits of the others.

You could also raise the pots up on 'pot feet' to give them better drainage.

oh dear, reminds me of my goldcrest which is also struggling right now.

Quick question - how can the wind damage this plant?

Cold winds and low air temperature can freeze the contents of plant cells, effectively drying them out. Softer new plant growth, or growth of plants not hardened off by a gradual exposure to the cold, can suffer and be killed.

The worst thing for them is salt spray. A lot of people use them as hedging as they are sold everywhere and cheaply. Come winter then the salt form roads is sprayed all over them and that causes them to brown.

They also hate winter wind and too much wet - they tend to have black rot rather than browning IME. I think that above is overpotting and resultant rot.

Thanks very much everyone for your help, I didn't realise that they didn'y like too much water which I think must be my problem