That looks really strange - are these three plants in close proximity?

there have been some in mine as well, they usualy make it through the winter, but this year are struggling. my garden has a lot of clay as well. maybe it's because it's been quite a dry season. could try giving them a really good soak, when clay soil drys out it shrinks which can cause air pockets which i'm pretty sure plants don't like, wouldn't hurt anyway.

The plants are fairly spread out, and it occurs in patches. It happened last year as well - one day you can have an apparently healthy plant and then this starts to happen. A few have perked up and survived but most die. Mostly they are at the end of the garden

I'm at a bit of a loss to explain this....could the soil be contaminated, perhaps by a leaky oil tank? A fungal attack is possible, but seems unlikely to me.

I'm wondering if in fact the three things are unrelated. The conifer dying back is not unusual in itself and could be fungal or environmental. Dead conifer branches will not regrow, so you might as well remove those. I'm not sure what's going on in the first picture, but it looks rather like leaf scorch (although seems unlikely at this time of year). The plant in teh final picture seems to be a bulb of some sort. This damage could be explained by lack of water and again looks rather like scorch, which is more likely with this kind of plant since the leaves are more delicate.

I think it might be worth sending a soil sample off to be tested. Are your immediate neighbours having any trouble?