Thank you to everyone who answered my last question and for all the good advice. It does seem that I have developed Plantar Faciitis - which is a disappointment as I was hoping to finish C25K in two more weeks.
As the pains first thing in the morning have been worsening, I have been told to hold off on the running for now and treat this with rest and stretching exercises. When it significantly improves I can get back into the programme gradually.
As I had finished week 7, I'm planning to keep up the momentum and stamina with a different kind of exercise routine for the time being and when my feet are better I will re-start the programme altogether as I have really enjoyed seeing my progress from week to week.
Thanks to all of you for the good advice and encouragement.