Well, if all the required investigations can be done at the CAA, then I would have them done there.
In the past, I underwent two cardiologic assessments with the CAA at Gatwick - one for ventricular ectopy and the other one for RBBB. Despite these two problems, I still hold an unrestricted Class 1 (though I was temporary restricted to OML for a year in the latter case).
I've found the consultants and the AMEs at Gatwick very fair and helpful. Rest assured that the CAA medical staff are not there to fail you. It is certainly not their mindset.
Wishing you all the best!