Being completely useless at these things... can anyone advise....is there a good facsimile for the stock S40/savage exhaust downpipe? Bits seem hard to get in the UK.  I did have a quick look on ebay as kindly suggested by a UK member but I get no answer from the company involved. I can't help feeling that I should extend my search to other part manufactures to see if I can replace it with something else. A bit like replacing the stock petcock with the raptor.

YOu mite be ahead to visit a few muffler shops & see about having one made. Remember theres an inverted cone just inside the inlet, where it goes to the jug, to hold back reflected waves. You can use the flange thats on it now, just dont go "too fat", youll lose torque. Look for a bike in the "employee" parking area..
Thats such a short piece, you may be able to find enough in their scrap pile & just pay for the welding & bending, Paint it, Wrap it, have it ceramic coated, have it chromed, or ride it,, its all good.