Not a Blue Thistle, but Eryngium - sea holly

A day of working at the computer and an evening of working in the garden. 
I moved a lot of nettles from an overgrown section of the garden, and I cut a lot of grass.  The cut grass is piled around our small horse chestnut tree to ensure it has enough nutrient and to keep the weeds down.  Horse chestnuts don't occur naturally this far north so we are treating it very nicely.
The Blip is of a blue thistle, one of the many Jan has scattered around our garden.  This head is just over a cm high.  The evening sun picked out the thistle heads while the rest of the garden was in shadow.
Correction - Jan has just informed me it's not a thistle at all.  It is sea holly, eryngium.  I stand corrected and have amended the title too
Yesterday evening the temperature went down to 6°C and today it was sunny but only 10°C.  Where did the summer go?