Spotted in the park this morning! iNaturalist seems to think it may be “Nezara viridula” but these are normally green (hence the Southern Green Stink Bug).
Insect experts – please tell!

Red Green Group/Friends of Perivale Park. Green Flag award 2022-2026.
iNaturalist is correct Henry. You confusion arises because it’s the adults which are green. What you have here are nymphs, probably 4th instar. Some of the instars are pretty colourful.
When I was working in my father’s garden yesterday morning I found over 30 nymphs & at least one adult on the flowering heads of some purple Amaranthus I’d sown. Frequently get them on Runner Beans here too but I pulled those up as they struggled in the hot, dry summer weather.