I also am aiming for a sub 1:30 HM. I set my PB two years ago in June 2012 (1:30:34) but have been injured twice since then, most recently a tibial stress fracture which had me on crutches for 10 weeks before Christmas which set me back considerably. Ran my first race back last Saturday which was a 10K and I ran a fairly comfortable 46:15. It feels like a long way to go to get back to around 1:30 for the HM but hopefully with some regular training I'll get back to those times. I'm sure you're capable of reaching your goal - good luck!
Does anyone know if platelet donation has any negative effects on training? I was asked to donate platelets at my last blood donation, and you can do it once a month, which is a lot more than the once every four months. They only take out the platelets, which are the sticky bits of the blood, and put the red blood cells back inapparently, so am I right in thinking that this shouldn't have as bad an effect?