Yes, as has been said, whether 'a' or 'an' is used depends on if it's a consonant or vowel sound, rather than the specific letters. For instance you would say "an historic occasion" rather than "a historic occasion".
And we refer to it as 'The' BBC because it's The British Broadcasting Corporation, just as we'd say The NHS because it's The National Health Service. Both acronyms end with a word which makes more sense when you use 'The'. Why they insist on "For BBC" is beyond me, apart from the fact it looked less messy when the BBC's branding was streamlined in 1997.
And we refer to it as 'The' BBC because it's The British Broadcasting Corporation, just as we'd say The NHS because it's The National Health Service. Both acronyms end with a word which makes more sense when you use 'The'. Why they insist on "For BBC" is beyond me, apart from the fact it looked less messy when the BBC's branding was streamlined in 1997.