This some what flexible. You are allowed 270 days total in three years and 450 days in 5 years. If you left on march 1, it will be counted as a day in UK and if you returned on march 5th, then 5th will be counted as in UK so you are only THREE days away. See if you can calculate again and may be you are not that many days away. Also, If you write an explanation, they wil consider it and if it was out of your control then they might consider it in your favor.
Read the absence section carefully and you will find your answer in it. This is not hard and fast, many things can be considered.