This is a quick note to explain how many pigs constitute a "complete" set.

There were 5 pigs in the original series: Woody, Annabel, Maxwell, Lady Hillary and Sir Nathaniel.

Then, in 1998, a further pig was introduced: Cousin Wesley, given to those who invested £1000.  This makes a total of SIX pigs in the collection.

You could even argue that there are 7, because Natwest gave away a further 114 golden Woodys in a prize draw in April 2006.  However, although these may be very collectible, I personally wouldn't consider them part of the main collection, because they weren't made available for everyone to collect - just those few who happened to win the draw.