|Hawthorn Shield Bug (Acanthosoma haemorrhoidale)|
Unlike many other insect groups, many shieldbugs are easily identifiable without specialist equipment and keys though a x10 hand lens is sometimes useful. The laminated fold-out AIDGAP Guide to the Shieldbugs of the British Isles produced by the FSC is a good place to start at a very modest cost if you are interested!
This is a reasonably common species I believe, although there are comparatively few records from Wales on the NBN Gateway:
Source: NBN Gateway