Could any one please tell me if this will be ok or have I made a
rather large mess because obviously, the waste cannot flow uphill and
I didn't know if there were any toilets with the waste pipe exit
higher than this.

You could always raise the floor in the bathroom by 70mm. This could be
useful for flush mounting shower trays and running concealed pipes if the
step into the room isn't a problem (i.e. there's already a step or change of
level). Just a thought, anyway. It's almost certainly quicker to redo the
hole, though, particularly if you've got spare matching bricks.

Christian.