Snakeskin brownie (Hypholoma marginatum) sounds more like a biscuit than a fungus doesn't it? I have no idea why it should be called that although it is two tone brown in colour. This is one of those common fungi that grow in big clusters or 'tufts' on, or near, rotting wood. This species particularly likes stumps of conifers and, of course, Forestry Commission woodland is where you expect to find stumps of felled conifers. It is found in late summer and autumn.
I think it is edible but don't try it until you have checked with an expert.