While an abundance of clay deposits made briquetage salt manufactuing in the humidity of Brittania it was not the only option. As a cheap byproduct of silver mining lead was a prevelant resource with a wide variety of uses throughout the Roman Empire. Lead was soft, malleable, and resistant to corrosion, making it ideal for pipes, roofing, cookware, and cosmetics among many other things. It also imparted a popular sweetness to wines and other iterms cooked in it through the creation of lead acetate or “sugar of lead” which is now known to be toxic.*
Per the UK Salt Association
"The Romans were the first to use lead salt pans to evaporate brine and produce salt. The pans used by the Romans were typically about 90-100cm square by 15cm deep. Excavations have yielded a number of such pans and we even know the names of a few of the Roman saltmakers thanks to inscriptions on some of the lead pans – Viventius, Veluvius and Cunitus. One pan is inscribed “COPI” which could mean it belonged to a Christian bishop – placing this pan in the late Roman period." These pans have been located near the sodium rich inland brine springs around Middlewich and Nantwich in what is now the county of Cheshire and I had the privlidge of visiting the Lion Salt Works Museum to examine thier display.
Unllike Brigquetage where salt was finished in smaller pottery vessels to create cakes of salt, it appears that pan salt was dried in conical baskets. These continue to be used through later salt pan history as well and we have depiction so them being stored nearby to facilitate drying. This would have allowed the salt to drain more easily and for the salt to be moved to baskets or bags once dried.
*For more information on the historical use of lead visit https://sites.dartmouth.edu/toxmetal/more-metals/lead-versatile-metal-long-legacy/