Shield bug? - NOT amateur radio

Our grandson brought this in the house this afternoon. It is ladybird size (about 5mm long) and I think it is a shield bug, although I am unsure.

Shield bug - NOT amateur radio

This shield bug was on a post near Lincoln Cathedral. 

It seemed quite happy for me to take its photo.

These are quite common in the UK on roses. They are a kind of beetle usual less than 1cm long.