BBC Four

Logical Channel Numbers are assigned by the platform, not carried in the transmission, which is why they differ between nations and why a retune can move them.
Channel number	Where that number applies	Multiplex	System	Format	Availability
9	England, Wales, Northern Ireland	PSB1 (BBC A)	DVB-T	16:9 SDTV
24	Scotland	PSB3 (BBC B)	DVB-T2	16:9 SDTV

On PSB1 (BBC A)

1,127 transmitters radiate PSB1 [V] — nearly every television transmitter in the country. By nation: England (638), Scotland (236), Wales (205), Northern Ireland (48). It is operated by BBC.

If this is missing, so is everything here

71 other services share PSB1. A multiplex is one 8 MHz transmission carrying all of them at once, so it arrives whole or not at all — losing exactly one of these and keeping the rest is a fault in the channel, not in your reception.

BBC OneBBC TwoBBC AlbaBBC ScotlandBBC Three (SD)CBBCCBeebiesBBC NewsBBC ParliamentBBC Red ButtonBBC RB 1BBC Radio 1BBC Radio 1XtraBBC Radio 2BBC Radio 3BBC Radio 4BBC Radio 5 LiveBBC Radio 5 Sports ExtraBBC Radio 6 MusicBBC Radio 4 ExtraBBC Asian NetworkBBC World ServiceBBC CWRBBC Radio BerkshireBBC Radio BristolBBC Radio JerseyBBC Radio KentBBC Radio LeedsBBC Radio ManchesterBBC Radio NewcastleBBC Radio NorfolkBBC Radio ScotlandBBC Radio UlsterBBC Radio WalesBBC Hereford & WorcesterBBC Radio CymruBBC Radio DevonBBC Radio FoyleBBC Radio LancashireBBC Radio NottinghamBBC Radio SuffolkBBC Radio SussexBBC Radio YorkBBC Radio nan GàidhealBBC Three Counties RadioBBC Radio CornwallBBC Radio CumbriaBBC Radio Cymru 2BBC Radio GuernseyBBC Radio HumbersideBBC Radio LeicesterBBC Radio LondonBBC Radio ShropshireBBC Radio WiltshireBBC Radio CambridgeshireBBC Radio LincolnshireBBC Radio MerseysideBBC Radio OxfordBBC Radio SolentBBC Radio SomersetBBC Radio SurreyBBC Radio TeesBBC Radio WMBBC Radio Solent (Dorset)BBC Radio StokeBBC EssexBBC Radio GloucestershireBBC Radio NorthamptonBBC Radio SheffieldBBC Radio DerbyBBC Information

On PSB3 (BBC B)

1,127 transmitters radiate PSB3 [V] — nearly every television transmitter in the country. By nation: England (638), Scotland (236), Wales (205), Northern Ireland (48). It is operated by BBC.

If this is missing, so is everything here

15 other services share PSB3. A multiplex is one 8 MHz transmission carrying all of them at once, so it arrives whole or not at all — losing exactly one of these and keeping the rest is a fault in the channel, not in your reception.

BBC Three HD5SelectU&EdenTBN UKLegend XtraBBC One HDBBC Two HDITV1 HD / STV HDChannel 4 HDS4C HD5 HDBBC Four HDBBC Scotland HDCBBC HDCBeebies HD

Which multiplexes should reach a particular address is the postcode lookup.