Hi Anna
We had a bulldog (actually from the bulldog rescue that you have been referred to - speak to Tania, she is a lovely lady) any way, she used to get a dry nose and it's just one of the things with the breed, we always used vaseline on her nose with no problem. It became a ritual, vaseline the nose, clean and dry the wrinkles, file the nails, clean the bottom..... our Bella (RIP) really loved all the attention, even down to the ear cleaning when she actually used to 'purr' :)
Good luck - and give your bully a big hug from us Tara x