Thanks for posting this Stringfellow, I had exactly the same experience (see March 2014 under This Month, seed sown Jan 29th) and I sent Stromy Hall the photo of their seed not emerging, alongside seeds which have come up well, in the same tray. They replied that the supplier had done a germination test in Dec. 2013 and found "a germination rate well above the EU standards". Yet I had 5% germination and uneven growth of what emerged, a classic sign of old seed.
I can only conclude that such germination tests are done in perfect, laboratory conditions that have no meaning for normal, garden sowing. I find it deeply worrying because lots of gardeners like yourself must be experiencing seeds not coming up – and probably blame themselves. Meanwhile they have lost time, compost, greenhouse or bed space and sometimes have lost the chance of having a crop.
I should be interested if anyone else has problems, especially if there is something to measure against such as when you sow two different batches of seed at the same time in the same conditions.