Response from KTR on my enquiry on this below. For reference I used dishwashing liquid as recommended and then used Fuchs Foam Filter Oil for the oiling.
Cheers.
"Product: KTR AIR FILTER CLEANING KIT
Question: Hi, I have recently purchased a KTR induction kit second hand. I am located in Australia and thus it is uneconomical to purchase this cleaning kit. Is a K&N filter cleaning kit suitable instead? Can you also please email me the cleaning instructions for the filter as I did not recieve any with my induction kit?
Answer: Hi, Do not use K&N filter detergent or oil with our filter- it could damage the filter and/or engine. There are no cleaning instructions with the kit. Use a small amount of mild detergent such as washing up liquid in warm (not hot) water, clean thoroughly then place a small amount of light filter oil in a plastic bag and place the filter in the bag, coating the filter until it is completely covered."