Hi RebsChooks, I am new here but also in the UK like you! Lots of the products that the other posters suggest here are not licensed for use here in the UK, which is a pain in the bum, as we cannot buy them easily! However, I too have a running battle with ruddy 'Chiggers' as they are called in our house and have just spent the morning cleaning, spraying and squishing the damn things.
I have several friends who have invested in Eglus, only to find that they have the same problem and I think that once you have them - they are going to wiggle their way in anywhere! It has become for us, over the past 8-10y, a case of keeping them manageable and trying to not let the buggers get us down.
We have tried Creosote, blow torching (mildly successful), Dergal (expensive and mildly good) and more recently a recommended product Perbio Chok (freaked me out with the Novi Chok thing), as well as all the normal DE, Mite powders etc etc etc. on a 3 day cycle.
The best solution I have found is as soon as the weather starts to warm up (around easter weekend I start) and have a good clean out, and unscrew everything I can and spray out the coop with boiling hot water and the bog standard red mite concentrate you can buy that smells like lavender. Blast it in all the cracks and crevices, let it dry and then sprinkle and dust about with DE. You can buy Ivermectin drops for pigeons, parrots and so on and we have started to use this on the chooks, withdrawing the eggs for a week, to be on the safe side. Then repeating every 3 months with the drops. I then clean out my coop every week, inspecting carefully for the chiggers. As soon as they start to appear again, then I wash out every 3 days until no sign of them again! It is tedious and a bit soul destroying tbh but it's the only way we seem to be able to control them at all. My coop & run is quite large and has been left bird tight since the avian flu control a few years back....but still they persist
