If you look at very old corroded iron parts they often show lines in the surface, this is wrought Iron. Blists Hill still work iron and a good example of an iron forge is Wortley Top Forge near Sheffield both have websites.
AFAIK Blists Hill no longer roll wrought iron commercially, only on the odd occasion. From talking to a chap working in the Blacksmiths, he said there were few people now with experience to work the rolling mill to the satifaction of H&S. I dont think pig iron is available now either as the mill recycled old ships chain.
Genuine Wrought Iron is so much better than steel and will last a lifetime. Even older steel seems better than the new stuff. A Railway Locomotive owning friend explained how rebuilding boilers with large amounts of new metal need careful maintenance, using a water treatment to help reduce the oxygen in the water and lessen the corrosion effect. New steel being that much purer apparently corrodes faster.