St. Day on Wikipedia.
 

The roofless old Holy Trinity (1826-8) on Church Street. According to this source, it was closed as unsafe in 1956, and un-roofed in the 1980's. SW 7315 4234. © Paul E. Barnett (2014). Grade II listed. A cross in the churchyard is also listed, as grade II.

Holy Trinity on Church Street, labelled on older maps as a Sunday School, presumably serving the old church. SW 7305 4234. © Paul E. Barnett (2014). Link.

The current Methodist Church is off Telegraph Hill at SW 7303 4271, and is dated 1913. © Chris Kippin (2022). Link.

The former Primitive Methodist Church (and later, St. Day Methodist Church) on Scorrier Street, at SW 7306 4258, identified by Janet Gimber. © Paul E. Barnett (2023).

Is St. Day Community Centre a former church? It stands on West End at SW 7289 4247. © Paul E. Barnett (2024).

O.S. maps mark Trinity Chapel (Site of) at SW 7289 4262. I haven't been able to discover anything further about it, except that an information board in the town says it was 13th century, closed at the Reformation, and the tower demolished in 1798 (implying that the rest of the church had gone before this?). Assuming the O.S. maps are accurate, its site now lies beneath housing on Balcoath, seen by Streetview in 2009. However, the information board implies a site a little further south on West End, now occupied by a house called Trinity House. SW 7287 4252. © Paul E. Barnett (2023).

There was a Wesleyan Methodist Chapel on Brickworks Hill at SW 7285 4246. Shown on old maps as a large L-shaped building, its site was seen by Streetview in 2009. This is almost certainly the same chapel mentioned here as being on Fore Street, dating it to 1848. The same source identifies its Wesleyan predecessor of 1825 on Fore Street, seen here, © Paul E. Barnett (2023). Circa SW 7280 4257.