Lovely photo.
I'm no expert on dragonflies, and I can't really make out how the colour would look from the top. The thorax looks green and brown/black? The abdomen doesn't look particularly blue, but it's hard to tell in your pic against the sky.
One other possibility apart from those already suggested, might be the Southern Hawker - very common in Southern and Central England and Wales, less common in Scotland except a few parts.
Here is a pic of one. I think the male has some blue on the abdomen, the female more greeny green with the dark colour. If it was nothing like this at least that's one you can rule out!
@merc1_clocks wrote:
I didn't realise just how beautiful they are
They are beautiful merc. There are a lot of these stunning irridescent turquoise males - called the Beautiful demoiselle along the river that runs through the bottom of my friend's garden.
I could watch them flitting about for hours! There's another lovely pic of them on P 52 in the link about freshwater habitats in my last post.
Twilight zone! Now my original post with the link (after Merc's) has come back.
Perhaps Lithium took it away to examine it 
One of the lakes I fish has a fair number of dragonflies and while fishing one day I heard a noise behind that sounded like a sheep munching the grass.
However looking round, there was nothing there but I could still hear munch munch munch pause munch munch munch pause and so it went on.
Then I spotted what it was, a dragonfly was laying eggs dipping them into the water along the edge of the bank, everytime it dipped it made the 'munch' sound.
Another time I had to wait over two hours to have something to eat when one decided to break out of it's nymphal shuck and chose just inside the top of my bag to do it, I didn't realise it took them that long.
This is one that has just broken out and is still expanding it's wings.
They are very Beautiful things. Looks lovely when you have a lovely River or Stream in the quiet countryside and their hovering around.
. Those pictures are Gorgeous!!.
I thought dragons were make believe creatures that spat fire
Damselfly nymphs sometimes decide to hatch out all on the same day, they swim to the bank, climb up as high as possible then break out of the nymphal shuck.
On one such day while wading in the shallower margins, I kept having to remove them from crawling up my waders and send them on their way, however it didn't stop one from getting as far as behind my ear and another from reaching the top of my hat. 
The trout appreciated them, they had a good feast.
