I'm not sure I understand this- a half marathon is 4x5k plus 1.1 km at the end.
I am not sure why you would want to start so slowly then speed up- it seems to me the way to break 2hrs is splits of 28 mins times 4 then 6 minutes for the last 1.1 km. Of course you may have splits which are faster or slower because of hills.
PBs since age 60: 5k- 24:36, 10k - 47:17. Half Marathon- 1:42:41.
10 miles (unofficial) 1:16:44.
Simon, I was breaking it into 5 miles - 5 miles - 5K
And as it turns out I didn't start out slowly, LOL.
AND there were hills!!!
Thanks for the words of encouragement guys, I wrote a recap in the race report thread