I was intending to book WeKnow or Addison Lee, but as soon as the strikes were announced they ran out of the type of cars I needed (a van or large SUV). Blackberry Cars also told me they had no cars. So I booked BlackLane. It's about $180 as converted to USD by my bank. But that includes meet & greet at arrivals, tip and up to 1 hour extra waiting time. This is from Heathrow to Canary Wharf at 11pm at night. I also looked at Minicabit, which would've been quite a bit cheaper, but they don't include tip and only give 15 minutes of waiting time, so the difference really isn't that much by the time you factor all of that in.