Thank you to everyone who replied - very helpful!

Today the appearance of these red lines has improved. So it seems certain they are not stretch marks. I got a few with my son but right at the end and as others have mentioned they are thicker and indented.

I went to the health shop and bought some sweet almond oil as I used this with my sons pregnancy and my skin was lovely and supple. I had been trying Bio oil and organic coconut oil but it seems obvious now that they weren't terribly effective for me...