Did it with McMillian in 2013 I think it was - and got my Marathon PB from that race...
That said, I paid 25 quid I think - and I see its 50 or 60 now. But they also have offers now where you can submit your times/plans and get feedback etc.
I'm pretty sure they have a template and couple of PDF's and send them over and over. The content of the plans is not wildly different to what you see on the plans around here like the Meno plan done by our [former?] person who knew stuff and hung around here - but also the plans you see in P&D book etc
