BBC NI didn't have a slide scanner until c. the latter stages of 1985/early 1986
I realise this conversation is about putting the testcard to air, so I may be misunderstanding you, but... no slide scanner at all? How did NI handle junctions between programmes that normally relied heavily on the use of slides? Or crash captions? Did they take the network feed (in vision only) or what?
BBC NI relied on Network for programme slides (for networked programmes). Until the late-1980s, we had network continuity during daytime hours anyway (with the exception of opts for regional news). Local continuity didn't begin until after children's programmes (weekdays) at 5.40pm and somewhere between 5pm and 6pm at weekends. Up until the late 1980s, it was pretty common for the local announcer to let the network announcer voice programme holding slides too. But, fading down network audio and voicing the trail locally was common as well.
Holding captions for local programmes were produced using printed card captions, as far as I'm aware. These were then passed through a colour synthesizer (similar practice for the globe symbol and clock). Some examples:
http://thetvroom.com/tvf/bbc1-ni-001.png
http://thetvroom.com/tvf/bbc1-ni-005.png
http://thetvroom.com/tvf/bbc1-ni-004.png
...and when the mechanical globe broke down, we got this:
http://thetvroom.com/tvf/bbc1-ni-003.png
This static symbol was also used in the days running up to the launch of the COW symbol in 1985, if memory serves me right.
In autumn 1984, at the time of BBC Northern Ireland's 60th birthday celebrations, they invested in new equipment which enabled electronically-generated captions:
http://thetvroom.com/tvf/bbc1-ni-002.png
...and although we were still stuck with the mechanical globe...
http://thetvroom.com/tvf/bbc1-ni-006.png
...we did get the clock hardware that enabled this particular pres device to be generated electronically...
http://thetvroom.com/tvf/bbc1-ni-007.png
I have no idea how the positioning of the 'BBC1 Northern Ireland' logo was ever deemed acceptable.