I know that many people are going to try to make the journey out to the suburbs for Friday's High Mass. Blackfen is not the easiest place to get to but there are directions on my parish website.
No black cabs out here (the cabbies live here but don't work here!) There is a minicab office at Sidcup Station. Alternatively, one firm I have often used is Avanti Cabs: 020 8850 1100.