Hi Mark,
Glad to hear you're exepcted to make a full recovery.
I had a similar experience 18 months ago on Protea, but looking at your situation I only now realise how lucky I was at the time.
I was diving to 30m and looking for Kaakap or Amberjack when something hit my foot. I looked down to see my foot in the mouth of a 2.5m Zambie. I immediately kicked down on his eye with my right foot at which it let go and bolted off.
I realised that I was possibly in serious trouble, dropped my weightbelt and started swimming up in a controlled way so not to burn up more O2 than I could being that deep down. I got to the surface and then assessed the "damage". Luckily I was not injured.
On recollection I could apply a few things I had noticed about shark behaviour. I never saw the shark that hit me, common with many encounters (notice I hesitate to call this an attack as I believe it was a territorial dispute or plain beligerence). It stalked me from behind. But I doubt that this was a predation, as when I kicked it, the animal vamoosed.
It was a "teenager", a smallish male Zambi of about 2.5m. Could be hormonal imbalances in teenagers that could make them do stupid, impulsive things. We have genarally always had problems with the smaller ones rather than the big ones, even amongst other species.
Sharks also try and incapacitate their target and the bite on the foot = a bite on the peduncle of a fish, i.e. loss of mobility.
What counted in my favour was that the shark hit my foot from behind at a right angle to my legs, and unlike fish, our ankles have a large range of motion. It literally knocked my foot out of its mouth and basically only held my by its gums. The directions of the scratches on my footpockets confirm this. This I attribute purely to incredible luck on my part and inexperience on the Shark's.
Although a nice war story, I brushed it off as not so serious, but after your experience I have a lot more to be thankful of than I gave credit for.
Joe has also had a Zambie come at him totally disregarding the fish he had shot. Luckily we all dive with reel guns and he was able to use this as a weapon and it bore the brunt of the encounter.
I really, really, really hate floatlines and now even have another reason to advocate the use of reel guns. although only very experienced spearos should consider reel guns when hunting big, powerful fish or when diving deep.
Lastly, you mention DAN and the speed with which they got you to 1st class medical attention. This is what really saved your foot and most probably your life. Shark's teeth have some horrible bacteria that could quickly have caused septiceamia and placed you in mortal danger. Any diver, especially those that go to Moz etc, not a member of DAN should have their heads examined.
Remember, there are no hero points in this game. Only funerals!