A Christmas Quiz, Prostrate Cancer

[Poleparrot]

19. Defeated Isles (not English!) invite loyalists (6,7) starts with A
37. Spring in Cornish Village? No, a king’s got the answer (2,5) starts with S

A clue to solving rather than the answer please. I’ve got all the others that have been answered here.
Thanks

[Stephen_G]

Adeste Fideles in an anagram of defeated Isles

[Stephen_G]

https://en.wikipedia.org/wiki/O_Come,_All_Ye_Faithful

[Mexican18]

37. A saint mentioned in a famous carol about a king.

[Poleparrot]

Still don’t understand why 37 might be St David, what’s that got to do with spring?

[Mexican18]

The saint has a fountain named after them in the carol. It is also a village in Cornwall.

[Poleparrot]

Ah yes, not St David! I had got the answer but not why, thanks everyone