That 11% figure included 'partly vegetarian'.

A more useful study "puts the size of the vegan population at about 2-3% and the vegetarian population at about 5-7%" [1].

From the article, it appears that only 2% of vegans, and 3% of vegetarians surveyed did so for religious reasons.

[1] https://yougov.co.uk/topics/lifestyle/articles-reports/2022/...