what exactly is the difference between a minicab and a black cab... mini you arrange in advance and black you pick up in a queue and pay through the nose? I paid £10 to go a mile and a half in the middle of the day.
Could you do the train from Victoria to Croydon then?
I don't know how to explain it exactly, as I've just a conceptual understanding - mini cabs are owned and operated by just about anyone with any kind of car, hence the warnings of ALWAYS checking their credentials... most times you're going to get a better deal with a (legit) mini cab company. Black cabs are = London Black Cabs - dunno, just the reputable, black cabs we've all come to know and love. They can also be booked in advance as well as just hailing one, but yes, usually it will cost more... simply because it's Black Cab. I'm sure someone's got a better explanation than that!
I just checked the cost for my friend going from the Finchley Central area to Paddington (Heathrow Express) when she leaves on Monday morning, and it's £26, which doesn't seem too bad.