So I managed it, but I think I might have overdone something in my legs.
I deliberately went as slow as I could (3.68km as oppose to around 4.2km for the 30 minutes), but the bottom of my legs were really quite painful right from the start. I couldn't really 'glide', it felt like I was just plodding them down each time. It got better for the last 10 minutes, but even then I was running through the pain.
My wife (Physio) had a poke around and didn't find anything bad earlier today hence I thought I would do the run. The pain has gone off quite after the 5 minutes walk and other than being rather red and sort of tingling, they are fine now.
The good news is that the slower pace is _much_ more sustainable than the pace I was previously running. My wife called about 20 minutes into the call and sure, she could tell I was running but we managed to have an actual conversation (albeit with very short sentences :-)). Cardio wise, I felt I could have continued running for a whole lot longer.
I think a comfortable pace for now is probably a little bit more than today but not much more.
So, one more run to go and graduation!
(P.S. sunglasses on for the picture my red legs! :-)).