I mentioned that there used to be a barbers around the back of Norwood Malfunction train station that did this. It was a successful route to, I'm sure, very nice jerk chicken until it wasn't and now there isn't a barbers there (seems to have been rebuilt as a solicitors, probably with a line in suing people for indoor barbecuing).
Back in pre-gentrification SE4, there was a similar incident, there was a make-shift cafe made out of random bits of wood by the train bridge on Mantle Road that used to do chicken and drugs. In summer they'd do the chicken outside. In winter, well, who wants to be cold. Admittedly, it could have been a guerilla operation by National Rail or the Met, who periodically used to remove the structure (amusingly, they'd usually wait around afterwards while they cooked up some fresh chicken for them). Generally took them a day to rebuild and start again. Now the site of wanky overpriced flats, of course.