Was Automist tested in a UKAS Accredited Lab?

Yes, the only requirement stated in BS 8458 is:

System testing. Users of this British Standard are advised to use a test facility that operates a quality system. General requirements for the competence of testing and calibration laboratories are described in BS EN ISO/IEC 17025:2005.

Automist Smartscan was tested at Warringtonfire, their UKAS Accreditation is available to download.