Nice to hear that Alfie is recovering well
I think you'll get lots of different opinions on this topic
I'm pretty much in the don't castrate unless there's a medical reason camp, having had entire male Cockers since the 1980s. My first boy was a bit of a humper when he was about a year old, but humping isn't always a sign that a male dog is obsessed with sex. He never showed any real interest in bitches and the humping phase simply stopped after a few months. In fact none of my boys have shown much interest in bitches and they've all come across in season bitches, and none has ever marked indoors (apart from one incident where young Sam got confused when there was a real Christmas tree in the house
).
One was castrated at about 9 years old when he started having some prostate problems and William was castrated at 15 months because he only had one descended testicle. I waited until 15 months partly in the hope that the testicle would appear, in which case he would have remained entire, but also because I wanted to give him time to mature physically and for his growth plates to close. There is evidence from studies to suggest that early castration before physical maturity increases the chance of joint problems, cruciate ligament ruptures and other diseases such as osteosarcoma. On the other hand, castration virtually eliminates the chances of testicular cancer.
So please do your research and decide what's best for you and Alfie, but if you decide on castration please seriously consider waiting until he's at least 15 months or so.