The new swarm colony is going great guns. Clearly there are no new bees yet, so in theory the numbers are declining, but it doesn't look that way!
I put the swarm into a hive with a deep brood box and two supers. Naturally, after the event I discovered that you should not add supers until the brood box is fully drawn and filled with brood, honey and pollen. This ensures that the bees actually keep the stores below the excluder, where they will need them for winter.
See blog title for further information.