I tried pretty much everything - rotating between 3 buckets outside and inside, bicarbonate in the bottom, eucalyptus/ tea tree oil, rinsing every ( and I mean every) nappy, bleaching the buckets before going outside.

What sort of worked for me - lid ajar except overnight ( can't stand smell in DS's room if I don't shut it then & used the smelly citrus circles ( as mentioned in a previous post) and washing at least every other day. Am thinking about trying the planetwise nappy bag idea - just have to pay off the c/c after going on a nappy buying spree