Swimming might be fine, it is for most injuries, I was told to stick to front crawl and use a pullbouy if possible. Stay away from breaststroke as it twists the knee. I was told to start swimming as soon as the incisions form the operation had scabbed over (and liberally apply plastic skin beforehand).
Get a referral to a private orthopaedic surgeon from your doctor.It'll be the best £150 you ever spend and better than waiting 6 weeks to see an nhs specialist.Followed by 6 weeks waiting for a scan.Followed by 6 weeks waiting for another consultation.......
+1 took me almost 2 years to get through the NHS system, first there's the "take some painkillers and rest it for 2 months" phase, then several different physios get a go at it, then you get on a waiting list for a consultant, then finally for the operation, throw in a few "it might be OK now" pauses in the process and it takes forever!
Neighbor (farmer / NT warden) paid £80 to see a BUPA consultant (who is also the NHS consultant the other 4 days of the well), got it diagnosed properly and was on the surgery list straight away, basically he was told £2k for the operation on Monday or wait 6 weeks on the NHS list.
Mine's just started aching and locking up again