Your delenatiis might seem slow but I think sanderianum wins the competion for the slowest growing paph! Mine last bloomed in 2011, is still trying to mature a growth.
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The second bloom opened on April 25th.
Another picture of the first bloom
Side view
Pollinated on April 25th with pollinia that I got from Leo Schordje from Paph. sanderianum 'Nov. 2012'. Trying to come up with a clonal name for my delenatii...