Thank you for your input guys.
Tom, you are right - non breathing arm does not have the same recovery as breathing arm, and could be more elbow lead. The 5km crossing was a good chance to work on different things and one of them was left side breathing. I am mainly a right side breather, but even the last few seconds of the video when I start breathing to the right you can see that the left recovery is lower also. Good points to work on, thank you.
We went to the Greek Sporades swimming around Alonnisos, Skopelos and "the 2 brothers" among others.
Stuart, thank you for the input and compliment. Another thing I wanted to try on that crossing was a different kick. In the pool I am sometimes aware that I lose momentum during breathing stroke with a 2bk. So I just wanted to give it a shot. I quite liked it, it was more of a soft kick to maintain stability/maintain momentum than to increase speed.
Perhaps you can also lend your expertise to another point. I don't think it's so visible in the video due to quality, but while I am breathing on the left side the left arm does not initiate catch until the right arm is almost entering the water which is closer to catch-up than I would like (and maybe why I perceive I am losing momentum?). The right arm initiates catch earlier than this while I am left side breathing. Any advice on how to fix this?
I may not be rotating to the same degree on left as on right as I don't have the problem breathing right side.