Leaving the Shanghai airport while waiting on a connecting flight

Hello. I'm flying China Eastern from Melbourne to London, through Pudong in May and I have a 17-hour wait for my next flight for London. Can I leave the airport while waiting on an international connecting flight (same carrier) and do I have to notify anyone of my leave? Since I won't recieve my checked baggage is it a problem in terms of security checks? What must I do upon reentering the airport if I leave? I've read that I don't need a visa for stays in SH shorter than 48-hours (I'm an EU citizen). Is this correct? Thank you very much for your help!