There is a cluster of these in a shady part of the garden. I'm wondering if they're poisonous or how I can remove them.
I'm in Ireland if that helps.
Agaricales apart from chanterelles are often hard to identify and easy to confuse.
Touching a poisonous mushroom is not dangerous. However when dealing with any mushroom you are unsure of, make sure you wash hands thoroughly after touching it to avoid getting any traces in your mouth.
As to getting rid of the actual mycelium, that might not be possible or even desirable. Fungi help break down organic matter and make it available for plants. You can simply pull and toss the fruit bodies if they bother you.
Not sure which varieties of mushroom they are, but even if they are poisonous, that's only the case if you decide to throw them in a casserole or fry 'em up for breakast, so just don't eat them. The mushrooms are just the fruiting bodies of underground mycelium, so getting rid of them for once and all isn't possible, but they will disappear on their own shortly. However, if you don't like the look of them, twist them off and dispose of them. It seems to be a very good year for toadstools and mushrooms, they're unusually abundant here in west London too...