It is my understanding that they usually purchased their wine, often from a religious organization that made sacramental wine. Making wine is a technical skill, and it requires grapes, to which many churches in northern climates would not necessarily have access.

In contrast, the production of wafers for mass was often delegated to the nearest chapter of women religious (since everything that was needed from flour to ovens was readily available). In Virginia City, Nevada, for example, the local group of the Daughters of Charity made the wafers with a hand-crafted wafer press that we found in the basement of the Irish-immigrant blacksmith who made it (after 1897, when the daughters left Virginia City, they entrusted back with the man who had crafted the tool). See images of it here and here. I deal with this subject in my book Virginia City: Secrets of a Western Past (2012).

I'm in a cellphone so apologies in advance that this is a bit abbreviated but during the era you are taking about the climate in the uk did not allow for the growing of grapevines so even if churches wanted to make wine the logistics of getting grapes from over the channel would have been extremely difficult and expensive. Even in America where grapes would have been more accessible it was made by commercial wineries. A few wineries were even able to survive prohibition by making sacramental wine.