If it's all set up correctly you will be able to receive BBC1 (all regions), BBC2 (all regions) BBC3, BBC4, BBC News 24, BBC Parliament (does anyone ever watch that?), CBBC, CBeebies and some other non BBC FTA channels.
If you look here
http://www.lyngsat.com/freetv/United-Kingdom.shtml anything which is on Astra 2A/2B/2D and Eurobird 1 will be watchable. You should also be able to get a few channels that Digiboxes can't as they are limited in their FEC and bit rates.
Whether any are
worth watching is another matter!
PaulR