I also found a couple of these Green Shield Bugs...
They are usually bright green but turn this brown colour in autumn prior to hibernating. I presume this is an adaptation so that when they're hiding away in the brown leaf litter, or whatever, over winter they're much more difficult to find. Clever biology is.
What I don't know is whether these ones subsequently turn green again - or do the lay some eggs and then die off fairly quickly?
I also saw my first bumblebee of the year but didn't see what species.