Bottom of conifer going brown.

Drought - that's what's caused the dieback probably, and no, the brown areas will not grow again, though the tips of them might.

Looks as if it could be caused by cats or dogs marking their territory.

Living in Glasgow, drought is unlikely..
There are cats around the tree's quite often though, trying to catch birds.
I have a mini conifer in my front garden which went brown a bit when a dog fouled it, I sprayed it with soapy water and it,s coming back green, wonder if that could be the cause.
can I move the tree?

Usernut, I see that the conifers are in a corner of your garden and this is an obvious marker point for cats. We have a similar, but much older, conifer at one of our garden corners and over the years the cats have made a significant brown indentation on it. They are our own cats and it is interesting to watch them claiming 'their' territory. Do you have cats of your own?

No, but we have a regular visitor in a cat called missy.
she is a neighbours cat (not the one with the conifers) and goes into everyone's houses. if we leave a window open, even an upstairs one, she will climb in and wander into the living room as if she stays here, Much to the amusement of Khia , my dog.
she is the community cat..lol, and sometimes even leaves her mark in my garden.

You could try moving the trees but don't do it till late autumn.

Hi user i had this problem last year.My dogs urinated on the conifer tree it had started to go brown at base,i tried everything but it just spread up the tree.In the end i had to remove it,horrible when u loose a tree like that