Hi Bigbloke (hmmm, that sounds like the sort of intro you get in...um....certain types of late night establishment...moving swiftly on)
As Chuck says, VP/CS and retractable gear might be a big step in your mind but it isn't a big step up in reality. I converted onto a C182 within days of getting my PPL on C152s and had no problems. Yes, there is another aspect to engine management, but within a few hours it becomes second nature. It's probably more taxing getting used to the increased size, weight and power than the extra lever!
Go for it!
Edited to add that the guys flying Spits and Hurris in the Battle of Britain had something like 10 hours on type before action. A Spitfire might even be more 'complex' that a C182, so that's impressive, and I've never been shot at on downwind whilst trying to remember my itchybum mnemonic...they were 