Big G - I wasn't strict at all re the order of the sessions, although I did always do the long run on a Sunday. I tried to avoid having consecutive days with the harder sessions though to allow for recovery. I think the races built into the plan are on a Saturday as this is when races take place in the US so that obviously means changing things around too. There was a good interview with Pfitzinger on Marathon Talk a while back if you haven't heard it already. I think the one thing he said he'd change would be adding more strides!
Well done on the PB Jugula, hope you enjoy the rest of your time in Spain.
Shades - sorry you've had to DNS your race, get well soon.
Also, just to add, if you look at the plan as a whole, it can seem quite daunting because of all the speed sessions. But I found it's easier to just take each week at a time as there's usually just one tough session a week and sometimes you may want to replace these with a race or a parkrun.
Big G, sorry for late reply, we travelled to Tenby today where we are staying for a few days. I'd recommend the P&D plan. I don't think it's that drastically different to the Shades level 2 plan in that it includes a long run, a mid week longish run and varied speed sessions, with easy runs in between. I didn't find the marathon pace runs too bad (although for the one with marathon pace in a 20 mile run I used a 20 mile race). The sessions I found really hard were the ones with half marathon pace included. I really struggled to get the pace I needed for these, but I do think they really help with half marathon times (good idea to book a HM a couple of months into the plan as I think you'd have a good chance of getting a PB). I think for a lot of these sessions I ended up doing a couple of the miles on the track! This year I also missed out a lot of the intervals in the final bit of the plan as I had ITB problems and didn't want to risk it. I saw these final sessions more as the icing on the cake and I think as long as you follow 80 per cent of the plan, that's OK. A lot of people on the P&D thread follow the 55-70 plan but I think I would break if I did that many miles. But I did up the distance on a couple of the long runs as I like to get lots of 20mile + runs in.