Why does the front remind me of the Austin Allegro. Maybe this was Harris Man's inspiration for the front of the Allegro.
Maybe it's the shape, framed by the silver trim and the rectangular lights, which are perhaps reminiscent of the Allegro.
However, compare it with a Hillman Avenger; the grille was actually lifted straight from that but with the twin headlights replaced by rectangular units. You can still see where the twin headlights should be (and still are on some Trident Clippers of the same era!)