Something to think about for those collecting, especially in the Peak District, Northern Pennines and Flintshire, or anywhere that had prolific lead mines: Semilanceata, like most fungi are aggressive bioaccumulators and are highly efficient at absorbing heavy metals from contaminated ground. This can be a factor even just foraging on roadsides from decades of lead in exhaust fumes, but is particularly more prevalent in old lead mining areas. High soil acidity also naturally increases the bioavailability and solubility of heavy metals.
Places that have old mining spoils, processing works and drainage soughs, such as around Youlgreave and Long Rake (to name but one area I'm familiar with), are known for being highly contaminated from historical lead mining. There are places where livestock still can't be grazed for long periods of time because of this.
This could also be a factor with other chemical contamination, I only mention lead because I'm familiar with exploring lead mines and works in the Peak District and North Wales and have read lots about problems with belland ground.
Here is a useful map from the UK soil observatory:
https://mapapps2.bgs.ac.uk/ukso/home.html
You can select overlays then filter for soil chemistry and all kinds of metals etc. The screenshot I've attached is from the Peak District, which will automatically show a lot of lead contamination, but it's worth doing more research on your hunting grounds and what is/was there.