These all need to be replaced and ideally in cast iron. Surprise, surprise, we have found that there is a cast iron foundry in Holmfirth (just down the road). J & JW Longbottom Ltd
seem to produce a wide variety of traditional gutters and rainwater pipes.
The major issue with cast iron is going to be the cost, but it is something that we need to investigate before discounting it. There are other alternatives such as cast aluminium and plastic, but it would be good to use a traditional material if possible. It would also be good to make sure that the gutter put onto the outbuilding matches that used on the main house.
This is just another thing to go on the list of things to do!