At this point the mistake was made, but I was not about to throw away the race. He looked ok, but as I closed on him he was not fighting, so I poised on his shoulder round the bend and took him just before the home straight. Finished strong, beating my PB by 0.5s. Consciously relaxing for 2nd 200 after looking at stopwatch. I'm sure I would have subconsciously slowed the right amount anyway.
Fast starts are normal, and indeed necessary.
Sitting on the guy's shoulder for a few strides before dropping him - this slowed me to his pace, I should have gone for a quick kill as we were inside the last 200.