I'm currently in the middle of an implant procedure, and can highly recommend Dr Ali Abdellatif at Covent Garden Dental Practice (not SE1, but not far). My husband had an implant done by him a year or so ago and has been very satisfied. Ali's very skilled, very into the craft and technology of his work, and very concerned for the patient.
I had one done at the Angel Dental Centre, (or Clinic),
Islington. I know, it's not SE1, but it was painless, I'm happy with the result and it was a total of £1500.
Prior to the nosedive of sterling my wife had a whole bunch of extractions preceded by CT scans, followed by 14 implants done by a dentist in Portugal for a shade over £10,000.
She now looks more like a movie star than she did before.
Incidentally she was quoted £28,500 for the work in the UK.
Insofar as such a procedure can be 'recommended,' then I was happy with the outcome... and it was far less painful than I anticipated. If you don't need a bone graft it should be about £1,800; the SE1 dental centre also offers payment plans I think, although I didn't use one - I paid half up-front and half on completion.