I originally wanted an era 3 only LMS based layout, I don't mind LNER as the station in my village was LNER but the next village was LMS. I don't remember any steam locos as too young for that (honest).
Growing up in the 70s and 80s and my first OO layout was the APT and a class 31 I decided to have a dual time line approach. Remove the steam from the layout and its 1980's, remove the HST and diesel locos and its the 1920's.
As the era 7 class 08 was sold out I did buy the GBRf version and have now ordered the GBRf class 66 with modern wagons and tankers so its a tri-time line TARDIS in the garden shed sort of setup.
TLDR I'm era 3 LMS / LNER, Era 7 & 8 BR and Era 11 GBRf freight only.