Parasteatoda lunata
Formerly Achaearanea lunata.
This spider was a challenge to photograph - it kept curling itself up into a tight ball and the instant it uncurled it ran. I eventually managed to get some photos of it in a more relaxed state in the pot. Although the ObsIdentify app was 100% confident about this spider's ID (once I showed it the right photo - it had some strange ideas about the others...), the Britain's Spiders book suggests that certain ID of this genus (as Achaearanea there) depends on examination of genitalia. I managed to get a photo of the epigyne through the glass pot while it was alive - not the sharpest photo but the shape appears to be correct for lunata.
female Parasteatoda lunata showing epigyne, near Gressenhall (Norfolk, UK), 2nd June 2022