Well it seems they have decided to stay. So I added more frames so that they would not run out of space, with ‘brood’ or eggs being laid by the Queen.
The bees take full advantage of this and over the next few weeks the colony expands, the hive getting taller and taller with shallower frames being added to the top. This is where honey will be stored and can later be harvested.
A note on frames: Bees will build comb in any empty space you give them. If you put fewer frames in than a box is meant to hold, the bees will build rogue comb in the empty space. This can cause problems and be a mess to fix.