Don't worry about it..you had him just over a week and probably did just as we did..several days with minimum handling until he settled in. But the RSPCA had him for a couple of months before that didn't they? I was told that only a quick check had been done when they found him because he was so traumatised but even so..... He was neutered just before I took him so if they'd taken that opportunity to give him a proper health check it would have been noticed.I just wish now that I had had him longer and been able to spot it myself. You are going to have one amazing bunny once he gets over the surgery he is such a character