luke harris and daryl lee had their first child three months ago and are now preparing to welcome their third baby .
gay couple will become fathers for a third time in a few weeks after enlisting the help of three surrogate mothers .
first child phoenix blue born on january 14 while daughter willow-star arrived in 25-minute labour on february 25 .
upcoming birth means the parents , from surrey , will have completed their family of three within just seven months .