Suction trap counts from the Rothamsted Insect Survey and SASA
AHDB yellow water trap data
AHDB supports the provision of aphid count data from a network of yellow water traps. The aphids are identified by staff at Fera. All the individual counts are available here: You can click on a region on the map to see the counts in more detail. Although the focus of the commentary on the site is on aphids that transmit potato viruses, there are graphs to show the weekly counts of individual aphid species.
This information will be summarised by crop in the AHDB Pest Bulletin but as a large amount of information will build up over time there also links to the full data sets from this page.