Check in times

I am currently looking at booking flightd, I already have my flight booked from Shanghai to Leeds (UK) and I am looking to book a flight from Sydney to SHanghai, I have found a good priced one that gets in at 9.40am, my other flight leaves at 12.35- will this give me enought time to go through passport control, collect my baggage and go through to check in for my other flight, I have heard rumours about China airports not being the fastest to get through.

Also, as I am in transit I thought I wouldnt need a visa but looking at list above UK isn't on their- would I need a visa to walk round the airport for 3 hours?