Elasticsearch 6.7.0 Homebrew install macOS 10.14.4 fails to run ERROR: Cluster name [elasticsearch_nathan] subdirectory exists in data paths

These are two different machines. This is my iMac, the other is my MBP. I wanted to test a clean install, i.e. not an upgrade, on the iMac to see if the problem on the MBP could be replicated. But I hit this problem instead.

Thanks

Nathan