Let's try facing the facts, whether something is new or old, everything has something that the other thing does not have. For example, Leyland Tigers were probably one of the most stylish, leyland nationals were probably one of the cutest, leyland lynx were probably the strongest and the darts were probably the smoothest.
Sounds like it; the Cummins L10 (also mounted midship in this design of bus) is what I remember in the great Flxible Metros and Gillig Phantoms that Tri-Met ran from 1988 to 2016.
that's not a proper Leyland tiger I remember.it does not sound like a Leyland and does not have the Leyland 4 spoke steering wheel or Leyland dash,leyland instruments were square
4 spoke wheel is old Leopard. And very old tiger, half-cab single-decker bus and coach chassis. Modern Tiger has Leyland turbo-diesel and sounds different to Leopard. Square instrument panel was obsolete as soon as the tachograph was invented.