@folbert YES!
This is the problem, I had a filter on the <body> class that removed the all important archive-service-data. Refined the filter and all is good.
Thank you so much - this was driving me insane, as I could see everything to do with the files was correct. Thank you!
FIX: the issue was self-inflicted - I had a filter on the body class that removed the archive-service-data class