That is one of the boxes that Philips have sent new updated software for.
So if your box wasn't on (or on standby) when this OTA update was sent your box will not have it. I don't use Philips equipment so no idea of the number or what it was for. It will most likely be repeated so keep a check on this website for details:
http://www.dtg.org.uk/industry/download_schedule.php
You are probably using the Winter Hill transmitter on which the BBC has changed Mux frequencies.
Try deleting all channels from the box by doing an autoscan with no aerial connected to delete all info from the STB tuner.
To avoid channels being placed in the 800s do a manual scan for freeview stations on main channels 56, 62, 63, 66 and 68. This should correctly assign all BBCA channels in the correct order.