[JMT1985]

They did move down one floor though. The newsroom was based on an upper floor, but come 1994 they had moved the newsroom down one floor. 

This can be seen when you look at the 1992 Early Evening News opening titles, and compare it to the 1994 titles - we can see there was a move down one floor. Maybe the floor below had better space and more room for a larger news studio, for the 1995 revamp, where the Morning News, Lunchtime News, Weekend News and news summaries all came from the newsroom studio?

That's right, when Grays Inn Road opened in December 1990 it had three studios. Studios 1 and 2 were in the basement and controlled by PCR1. Studio 3 was alongside the atrium on the first floor and controlled by PCR2. That's where the weekend bulletins came from and eventually the EEN as well. I do know that a second atrium studio was built on the ground floor and was named Studio 4. That was still the name of that studio when it was used by the ITN News Channel and ITV London in the 2000s. Studio 3 must have been removed at some point, although I'm not absolutely certain of when and why. For instance, did News at Ten join the EEN in Studio 3 in November 1992? Or was Studio 4 built for NAT in 1992 and the EEN and NAT were from different studios on separate floors? Or did the move to Studio 4 happen at some point in 1993 or 1994? I'm afraid I'm not certain about that. Certainly by 1995 they were in Studio 4 on the ground floor.

I believe News at Ten in 1992 was on the same floor as the early evening news. The moving down one floor didn't happen until 1994, at the same time the News at Ten moved into the basement studio. So it seems News at Ten was on the same floor as the EEN from November 1992 until around September 1994. 

ITN must have felt that moving down one floor had better studio space for them, and so used this chance in 1994 to move News at Ten into the basement to share with Channel 4 News, and then make a better atrium studio with Studio 4