A shieldbug of some description
No interactions present.
Squashbugs are very closely related to the shieldbugs, as you noticed.
Thanks Diocria for the identification, this is a new one to me and I would never have found it as there is not a single reference to it in any of my books.
This individual has unusually narrow 'shoulders' but it is definitely the correct species
Details updated to agree with comments on the identification of this insect. Thanks for your responses
Thanks for the identification. Details revised accordingly
Lat/Lng: 50.406548264293, -4.1054025292397
OS grid ref: SX504584