weise i dont think one can tell from just one cycle,you need to tell me ur normal cycle length (days)not just ur LMP,because your last cycle was quite long (24th jan-5th march/40days). If u had ovulated in that cycle,it wud have been between 17th-19th feb. But I think u havent ovulated in that cycle, as a normal cycle lies between 25-35 days in which a women releases an egg. A longer cycle normally indicates that u have not ovulated (if not fallen pregnant), a condition called anovulation. As you suffer from pcos, anovulation can be a "side effect" of it. You should really see a gynaecologist for treatment such as clomiphen or Metformin(unlicenced drug for use in pcos)..to help u ovulate.
well for this month if your cycle is 40days and your periods have started 5th march then ur paek day will be between 29th March- 31st March, you should have intercourse from 28.3.
I would still advise you to see a doctor.