How to Cook 3 episodes

Hello, I have tried and tried to see the television episides of How To Cook series 3. I purchased the original series 1 & 2, could not purchase series 3, have looked and looked to see any screenings ANYWHERE of these TV episodes on any of the food networks, iplayers, or online elsewhere (even, I must say, the library). (Given the work which must have gone into this series on Delia's part I am amazed). I saw the series purportedly for sale at https://www.ioffer.com/i/delia-smith-how-to-cook-complete-3-series-6-dvd... but do not know if this is a scam. Do you or Delia know if this is a genuine source of the TV episides for How to Cook Series 3? Or, otherwise, how I might see these? Many thanks, John