When I smashed up my shoulder (fracture & dislocation) a couple of years back I was told by the consultant that it would be 3 months before I could get back to boxing. This is also what the physio told me when I was working through rehab exercises. However the physio also said I could get back into BJJ after 9 - 10 weeks as long as I took it carefully. Personally I'd suggest getting referred to an NHS physio and following their advice rather than going back too soon before it's had time to heal properly. I was training with someone at BJJ last week who'd returned to training too soon after being hit by a car and he kept having to stop because he was in so much pain. It can be frustrating having to wait so long and there will probably be people on forums who suggest you can return earlier, but I'd definitely get advice from someone with qualifications.