When you do the Boar you will be able to say you have done an official middle distance event, that is the same as a half Ironman...
Don't understand why you say doing the Boar is good practice before you do a proper one !
A) you might annoy the organisers of the Boar
B) do you think it is going to be any easier because one has an over hyped American title ?
You might note that the World a Triathlon Corporation never call them Half Ironmen anyway. They always call them 70.3