We have assessed the efficacy of filtration versus precipitation methods and shown (in common with other researchers, e.g. Spens et al. 2016) that detection probabilities are higher using filtration. This is likely because the standard GCN eDNA Kits only process 90 ml of water, while our Aquatic eDNA Kits that use filters have been designed to deal with the high turbidity of ponds and typically process an order of magnitude more water. Filters pose less logistical challenges because they do not involve ethanol, are easier to process in the laboratory, and are much less susceptible to contamination. Unfortunately, a move to filtration is not up to us, but the evidence has been made available to Natural England along with contact details of independent scientists who they can consult. We hope that results derived from these kits may be accepted in coming years.