Do you have PHI?

Worth going to your GP and ask for a referral to see a specialist. It would not be considered cosmetic surgey to correct it surgically if it's determined to be medically necessary.
A GF had it done, it was very painful and recovery was very slow, at least 3mths.
The procedure itself was relatively quick, she also had liposuction at the same time and again it was claimable through PHI as it was considered medically necessary.
She was no where near as fit as you so your recovery time maybe better if you want to go the surgical path. The result was a flat as a tac stomach, it was quite amazing to see as she always had 'overhang' when wearing jeans.

A decent Physio also would be able to determine if it is 'fixable' or not without surgery.

When you have seen both Physio and GP, then the decision would be left up to you which way to go.




ETA: her separation was the same as yours.