wow thanks for all the input,great advice from all, will hopefully sort it out with bigger diameter flue also will try the skirts on the sides,maybe with small openings in for longer material. the sizes are 7in going into 7in to 8 and a half double lined pipe then reduced from 8 and a half to 5 up the top, thinking the choking would help the draught!! the blower is called a PIERCE ORIGINAL BLOWER it comes with the larger wheel to drive it usually by a leather strap or belt, but i use an innertube from a bicycle. I think they were used to lite fires in big houses, works fine in my forge, better than the electric blower in the 3rd photo. once again many thanks for the help. cheers chris.