Going back to Gatwick may indeed be the easiest option and if everything is ok and you get your medical that will prove the best course
However if the CAA are not happy you are left with no cardiologist to fight your corner as the CAA can't argue with itself. Many pilots have found it beneficial to go to an outside doctor who can not only perform the tests but dispute the clinical significance of a borderline or less an normal result
PM me if you want some names. You would be able to get a quote before committing.