Traditionally Christmas puddings were made on "Stir Up" Sunday which is the last Sunday before the season of Advent.
The term comes from the opening words of the collect for the day in the Book of Common Prayer of 1549
“Stir up, we beseech thee, O Lord, the wills of thy faithful people; that they, plenteously bringing forth the fruit of good works, may of thee be plenteously rewarded; through Jesus Christ our Lord. Amen."
This will give the flavours time to blend and mature - I think this year it was yesterday, so anytime around now should be perfect
All the best
Sue