HA cloud, Alexa and entities

I’ve been using HA for several months now and wanted to take the next step and use the Nabu Casa cloud, not least as I wanted to link more closely with Alexa which I also use extensively.

So, the account is set up as is the linking. However, when I come to enumerate the entities to expose, the ui just hangs. To be fair, I do have a significant number of entities configured, but even if I leave the enumeration to run to several minutes, the list is never returned.

Can anyone shed any light on this?