Not all units are going to go through the interim program. Originally intended to be one unit done, which was 450111 for TV appearance.
Then went to a further 9 units to have "ten example" units in service during Summer. Now interim work extended due to delays in the full refurbishment kicking off.
There is only about another 6 units to go until it stops pending introduction of full refurbishment. No 444s have been involved with the interim work.
450 Interim Refurbishment units: 450003, 006, 007, 010, 013, 014, 016, 020, 024, 025, 027, 028, 030, 031, 033, 035, 036, 038, 040, 041, 073, 074, 075, 079, 086, 093, 099, 102, 105, 110, 111, 124, 126.