maybe im in the minority here but if shes happy then keep her up a bit longer - i think its pointless trying to set a sleep routine till bub is at least 6mths. (by that I mean a set bedtime, not the routine before bed if that makes sense?!)
just put her in a bouncer, or on the floor with some toys for another half hr, then try bedtime again.
I know its hard when youre tired etc, but I think its worse to try and force sleep if its not working.
Sorry hollye, I know its prob not what you wanted to hear?!