Contacted Achmore of Alfreton regarding bulk purchase of wood preservative. Both staff I spoke to offered really good advice, both on their own products but also other companies. There prices were really competitive. I bought their own preservative. Put 2 coats on. One by brush., the other using a cheap sprayer. Both methods were easy with little or no mess. Which is a first for me. Clearly only time will tell if the preservative is any good. But if it is as good as the Ache service, I'm sure that I won't need to protect my fencing for some years to come.