Hi Wobbler, I've just this morning got back from seeing my sports doc who has taken me from 'diffuse abdominal and groin pain' through to now going to see a surgeon.
I'd recommend seeing someone like that (PM me if you want his details) to get the inside track on this condition.
Like you, I'm a triathlete, similar amount of training hours/week and same age (guessing from your '75 nickname). I had a MR arthrogram a while ago which didn't show any hip trauma (but they don't always) and I've been going for physio once a week for the last six weeks and also working on core strengthening.
My core has improved and the treatment has helped identify where the pain isn't so now I'm in a situation where the options are:
a) carry on with physio
b) have a steroid shot
c) see a surgeon and potentially have surgery.
as I understand it, a) if it works, will take a long time and will not treat the underlying problem b) will get rid of pain but not treat the underlying problem c) ... I'm sure you can guess c)
From my standpoint and with limited, non-medical knowledge, I don't think physio can repair a labral tear, I think only surgery can.
On the bright side, it could only be 12 weeks off!
Best of luck and let me know how you get on.
FWIW, I will be seeing the surgeon and if he says it would be a good idea, I will be having surgery ... after 2 years of pain I can deal with 3 months recovery!