Hi Julie,
There are no other pieces, just an entrance hole and the entrance piece.
(Inside you should have a nest form, and ideally partitions to keep the birds safe within the eaves, such as this Action for Swifts product if it will fit your space:
A front entrance box would probably be called a fascia box, as the entrance is through the vertical fascia board rather than through the horizontal soffit.
This is less often possible as commonly fascia boards have a brick wall behind them,
but if your building has a fascia board with a suitable space behind then yes that could work and Impeckable's entrance pieces should work too.
I suggest speaking to Action for Swifts for the internal box as they might be able to tailor one for you, as the entrance would of course need to be in a different location.
Hope that helps.