Sorry it's not clear but are you newly qualified or experienced? Well at the end of the day TO and LDG times are not required for you to total up time, can be a bit difficult to prove night flying time though. What I'm amazed at is the amount of people who will have seen your logbook in the past and not corrected you!
Years ago, I logged all my PPL training flights without separating legs. Example, if a flight involved going from A to B, then B to A. I would log it as A-B-A with the total journey time all in one entry! This got accepted by the CAA beleive it or not.
If you have the opportunity to obtain the times from another source then do so. Otherwise a good guess should be enough.