I'm sorry to say but although it's an added expense, best to have had the stump completely ground out when you had the tree taken down. I don't think that drilling holes and pouring various chemicals will solve the problem. You can just leave the fungi to break it down but it might take up to fifty years to do. So I would just remove the fungus if you feel it's unsightly but its down below that the fungus is feeding and you are only seeing the fruiting heads, so to speak.

I agree with the above. however removing the bracket will prevent more fungal spore entering the air and this will reduce the risk of further 'infection' as these spores germinate.

Thankyou Jimmytheone and SBG. It's as I feared. It really needs to be ground down which begs the question as to why the tree surgeon didn't suggest it. For now, I'll cut the fungi off to reduce the risk of spores infecting other oaks, although they fascinate me. At the moment they look like lovely bread rolls but will later develop into brown brackets.

I found that you have to specify to the tree surgeon that you want the stump grinding.

Hi, a lot depends on whether you used a qualified tree surgeon, or a bloke with a chain saw, if the latter, he could probably not be able to buy a stump grinder, they are very expensive, and most people just need a tree to be cut down, and are not bothered about the stump, Derek.