Hi Ant, and welcome to the forums .. from what I understand you would like to try something similar to AB - 10k training to marathon
18:26 is our starting marker .. what I need to hear from you is to what is the longest run you are used to currently, please?
for future tips relating to the 10k programs see:
whereas you can train on the sub 45 minute schedule, we need to change the pace according to you level currently
2k pace will be 4.40 to 4.45 (this session is quite tough to adapt to)
your 1k will be 10 seconds per k quicker .. 4.30 to 4.35 per k
we will look to establish a consistent routine and then after 2 cycles we will need to focus on getting the long run up to a decent length
on we go