Thank you for your question!
As a fellow Queenslander I completely understand what you mean about the hot summer!
I haven’t had personal experience with doggy body suits but there are a couple of options that are worth exploring.
Bromelli have made to measure sunsuits to help protect short-haired dogs from the strong Australian sun - they are also lightweight and should not make your bulldog overly hot - you can find out more from their website: https://www.bromellidogs.com.au/
Another great company I met at the Dog Lovers Show in Melbourne this year but who are based in Queensland is BeachMutt -The jackets are easy to put on and take off, are lightweight and UPF50 rated their website can be found at: http://www.beachmutt.net/dog-health.html
Dr. Alex Hynes