Mike,
There are loads of big enamel coffee pots on Ebay for under £20, a lot of them new.
From Trout Bum -
“It took A.K. to teach me how to make real camp coffee: bring one pot of lake or river water to a rolling boil, add two palmfuls of generic coffee, and remove the pot to the edge of the coals. If it’s the breakfast pot, throw in the eggshells. When it’s done (five to ten minutes), add a splash of cold water to settle the grounds.
Like whiskey, it should be drunk from a tin cup.” – John Gierach, Camp Coffee
John uses a percollator with the innards. I have used this method most times the power goes out in the rural areas that I have stayed in. I haven't had a proper fishing camp since before I met my wife (what does that tell you?) but still once or twice a year when she is away and I am feeling nostalgic I will brew up a pot. Tomorrow morning might just have to be one of those!!