These were the recommendations of the EMC test centre and were required to pass EMC testing to filter out the switching noise from the SMPS. After going through the manufacturing and procurement process we’ve now got a good relationship with the power supply manufacturer, they’ve suggested it should be possible to get the power supply to pass EMC without so many additional components, and they may be able to help with this and do some preliminary testing. However, for the moment we’re stuck with the current components unless we want to pay for another batch of EMC testing. This is something we may consider if we need to make other changes to the design.