There is a company in Melbourne called PATS ( Pilot Aptitude Training Systems) . They got myself thru the Qantas process , and also dozens of my workmates over recent months. Specialise in the Qantas process which I guess is similar to BA aptitude tests, and in my view are excellent.
I don't know a whole lot about the Pilapt tests though, PATS have some sample questions on their website(
www.!!!!!!!!!!!!!!!!!!) have a look to see if they are same.