But when she got there, the cupboard was bare

Here's the swarm notification chain from WhatsApp group:

[10:25, 5/29/2018]  Swarm in SW19 7EP any one available (message is 15 mins old from public)

[10:28, 5/29/2018]  Spoken to the man, swarm on a post about 3ft off the ground about the size of 2 Rugby balls long and 1ft wide

[10:45, 5/29/2018]  Max is en route to collect it.

[11:08, 5/29/2018]  Now THAT is a swarm

[11:48, 5/29/2018]  Update, the rapid response unit (aka Max) attended the location only to find about a cup full of bees left at the location, lots of bees flying around, if they settle Max will re-attend.

[11:49, 5/29/2018] Bad luck Max. Not rapid enough it seems!