The guidance we give on the selection of learning log entries recommends 2 to 3 for each learning outcome, which would equate to 8 to 12 learning log entries overall for your unit. Though we don't have any specific restrictions on the selection of learning log entries, or the number of times you might select 1 entry for more than 1 learning outcome, or the length of a single entry etc. it would make sense to show a breadth of entries from across your studies. This would help assessors gain an insight into your learning journey and how you have gone on to meet the learning outcomes of your unit.
If you feel that this specific learning log entry strongly evidences the meeting of all 4 learning outcomes on your unit in a clear and succinct way, and you would very much like to present it at assessment for all 4 outcomes, then you might want to ensure a selection of 2 learning log entries for each learning outcome in addition to this to show that breadth of learning and meeting the outcomes.
I hope that this helps Lee.