On a perfect day 1:14 is worth 2:35. I would say that that would be pretty hard to do on 100k/week. 2 weeks out is also cutting it close to race all-out. I wouldn't worry about windy conditions. Sometimes it's a wash if it was cool & windy. If the weather is good for London I would aim for 3:45ks/6:00 pace and put 2:37 on the table. If it's a little less than ideal I would go for 2:40. Some of the early miles are pretty quick 3/4/5. I would resist the temptation of banking time there. Miles 1 & 2 are slightly uphill so it's ok to run even 6:05-6:10 effort (maybe a couple of 6:15s) there & then settle into 6:00 effort by 10k. Even with the downhill miles I wouldn't drop anything super fast. Get to 10k right around 6:00-6:05 avg. & then run as many 6:00-flat miles as you can.