I've noticed tiny flies around my bathroom sink where the mosaic tiles have collapsed around the sink, leaving a hole. I think these are drain flies, and I squirt cleaning fluid and mould/mildew remover around the area every day, but I don't know what to do to get rid of them permanently. Any ideas?
They're definitely a thing- I think they are linked with damp/mould/mildew. I chucked a load of carbolic acid down there so hopefully that may kill whatever they were feeding off. nice.
If the chemicals don't do the trick, you might want to think about getting a small ' hand held steam cleaner'. Its about the size of a kettle and has various attachments for getting into all those difficult nooks n' crannies.
A very versatile little tool to have around the house.