Lynda,
Bullecourt seems most unlikely, it is in France, east of the Somme battlefield, and quite a distance from Flanders. The fighting there took place some time before the period you are looking at (April '17). Certainly railway troops were laying track up towards the Bullecourt area as fast as they could in March/April 1917, following the German withdrawal in that area, but everything you have said points to 3rd Ypres in this connection.
Let me know if you strike out at the NAA. I can probably give you hand getting info (living in Canberra has some advantages!)
And you have my sympathy - I've recently spent some time deciphering my Great Uncle's creative spelling of foreign placenames.
Good Luck
Duckman
*BREAKING NEWS*
Look at
this map
A couple of kms NE of Poperinghe is a village called Perelhoek (I think - I can't quite read the map). Might be Peselhoek.
Looks like Johan was on the mark (to no-one's surprise).
Mystery solved?