Tiles are 15×7.5×0.5cm
This can often be a tricky one! “Christmas at the Prendergasts” has no apostrophe because the family is plural. If it read “Christmas at the Prendergast’s house” it would have an apostrophe to show the house belonged to them.
But some may feel that the word “house” is there – just silently. In which case the apostrophe is needed.
If you would like an apostrophe then please STATE IT IN THE ORDER BOX, otherwise your tile will not have one. Of course you could just avoid it by having the other phrase “A Prendergast Christmas” 😉