A ton of automated scraping is what it needs. Just the main UK supermarket chains would do, as it seems rather British in the choice of products even though there's no pricing actually shown.
The packages are changing so fast/often now that the shelf labels, online sizes and unit prices are often out of date. (Yes this is illegal, no nobody cares because it's £0.05 per product and they aren't doing it on purpose, they just don't make it a priority to have correct data).