2021 - What I did today

Today I emailed Gardener's Question Time to ask them for advice on stopping red spider mites taking over my greenhouse again next year. I've never submitted a question before, I hope it gets read out sometime!

I haven't got those but I seem to have fungus gnats all year round  turn my back and bang they are there. I also had a few tomatoes with white fly on last week...so today I've made a start on cleaning it out. It was very wet, lots of rain so I could t use the jet wash. Just scrubbed it out with soapy water and bleach. Will give it a jet wash when I can empty it. 

How often do you clean it?
Are there any ladybird/bugs etc that you can introduce to control them?

I cleaned it when I replaced the broken panes this spring just gone. All except for the grapevine stump that was just starting to grow in the corner, and which was obviously where the blighters were hiding, ready to spring onto my cucumbers, melons, DFBs and French marigolds as soon as my back was turned.

I hear there are some predatory midges or some such I could try if they do come back, but maybe there are preventatives or fumigation tricks I can use.