The Chimney Sweep does not generally clean out the Ash-pit below a fireplace, as these areas can sometimes be cavernous and time consuming.
If you wish this done, TELL the sweep when you book the appointment so that they can arrange their time and inform you of any additional charges.

The homeowner should make it their responsibility to remove this ash themselves. One or two buckets a week until empty.
We have personally seen ash-pits with wood beams running across them that have been blackened by falling hot embers and ash that has been swept into them. This is a potential fire waiting to happen.
We generally advise people NOT to use them if they can avoid it and to fill them with masonry.