I saw Nigella on TV making little truffles from leftover Christmas pudding. During the show she recommends a specific brand of sherry for the Puddini Bonbons. I didn't quite catch it, so I'd be really grateful if you could let me know the name. Many thanks!
The sherry used by Nigella in the Christmas Puddini Bonbons (from Christmas) is Pedro Ximenez. It is a type of sherry, not a specific brand. Pedro Ximenez, or PX, is made from grapes of the same name. The grapes are allowed to dry slightly before being used, giving a dark, sweet sherry. You should be able to find the sherry in larger supermarkets and some off-licenses or liquor stores.
Nigella uses the PX sherry in her Ultimate Christmas Pudding, so will have it in the cupboard already. However if you don't have PX sherry then sweet Marsala would be a good alternative as it is made in a similar manner to PX. Or if you have used a particular liquor in your own Christmas pudding then you could also use this as an alternative, slightly reducing quantities if the alcohol content is very high.
You could also make the bonbons using rich fruitcake instead of the Christmas Pudding.