Stylesheet Missing

Hi There,
Both source and destination platforms are using WP 4.2.2.
Export runs just fine, Import runs just fine.
I have saved permalinks twice.
Enabled Plugins.

Site reverts to twenty fifteen theme, and when I go to change this, I see that the desired themes stylesheet is missing.

Any suggestions?

Thanks
Ian

https://wordpress.org/plugins/all-in-one-wp-migration/