I've learnt the hard way, it was the first running injury I'd had, I was setting pbs every race, push on, it'll go away, except it doesn't go away if you keep training on it. The PF took another cortisone injection, physio and six months off to solve. If I'd had a week or two off at the start it'd have been fine.
I had four 30/500 co-codamols, a diclofenac, and half a tube of ibuprofen gel ib my sock to race a 2 mile relay, quite possibly the most stupid thing I've ever done but I didn't want to let my club mates down. And it still hurt. I went to the GPs the next morning and had a bollocking and cortisone injection which hurt even more. PF is best rested before it becomes chronic.
I'm no expert (see below), but I can see that you need to rethink your targets for '15.
I did my first Tri at Outlaw this year. Almost 12 months to the day before I broke my ankle training for Chester Marathon (it was on the track, IIRC I'd just done a good sub 6 mile which was getting back to where I was before my previous injury), I was running 35+ miles per week in July 2013 and swimming once per week. I never really built my running back to where I wanted it to be before I started Fink and that hampered me showing in a marathon time well over 2 hours off my standalone PB, in fact I walked the second half at Outlaw.
Like Dave I looked back and I covered about 2500km in the first seven months of this year on the bike (including turbo), was dreadful running never going above 10 miles and swam 2-3 times a week for an hour with one open water session per week from about May onwards. I did nowherenear enough training IMO and my splits were 1h37/6 mins/6h39/5 mins/6h16 (hopefully that adds up to 14:45). I started the plan way behind with the running, I hurt my ankle again last November so started the plan in January on the back of zero miles in December and 101 miles in the second half of 2013, I'd normally have done 750-1000 in 6 months. From then on I was on the back foot, at the start of the plan I struggled to knock out a 2 hour ride Saturday and then an hour or longer run Sunday, my legs were shot within a few miles of the run. I found that my ok bike fitness didn't translate into good running fitness.
My advice, FWIW, is get fit to train before Christmas and focus on the 140.6 from January to race day. Forget about London, sods law says 2015 will be my ballot year but I'll defer it. It will be very difficult for you IMO to racea marathon and then get back into training, the old adage is a day per mile to get over a running race. RacingLondon would wipe you out for most of May IMO. You'll need to be cycling, cylcing some more and, when you're sick to death of cycling, out on your bike. Fink has rides up to 6 hours IIRC, if you're riding at the pace you're riding at now, that's not enough, you'll need to be covering 100 miles by June next year. Unless you're fit, you can't do that on a Saturday and then run for 3 hours on a Sunday if you've not touched the bike in the first four months of the year.
Each of us are different, and I don't intend to scare you, but my experience from this year was that I had to work hard to get fit to get around in a relatively slow time. The photo I have on my desk of my son and me crossing the finishing line was worth every single bit of pain in training and more.