Wood stove/gas Flue Pipe, short piece (Saltdean BN2)

I'm looking for an odd piece of stove flue pipe about 18" to 2 ft long (50cm) or longer, about 12.5 cm diameter (about 5 inches) probably cast iron or enamelled steel, maybe with stove collar ? or not. Actually for a gas - wood stove but any stove pipe will do. Do you have anything like this ? Thanks Richard