Earlier, I suggested a TT:120 train pack containing a green 08, some wagons and a brakevan. this could also be delivered as an "Inglenook" trainset, containing points, track and an instruction booklet about inglenook layouts and how they work.
Of course, this might be advanced thinking for Hornby, who can't move beyond an oval with a siding.
With a bit of sideways thinking, they could also look at separate complete track packs, like the Inglenook or a ready to go Minories*, for example. Neither would take up excessive space in TT:120 and would help get new entrants to the hobby away from the pernicious oval.
* With a reprint of the CJ Freezer article in RM from April '57 and with FULL instructions on how to emulate it using the track provided.