Hi Pupsie, Try Stayz.com.au and airb&b (people renting out their own homes for short periods). It will be Winter then, so rates should be reasonable. We just stayed in Meriton Serviced Apartments and they were great. Good locations, spacious, full kitchen etc. As for location, it depends what you want to be near - CBD? Beaches (maybe not in July)? Good luck - Sydney is fab!
Thanks for that! Not sure where we want to be. We're trying to tie it up with seeing Pink in concert. Thought we could make a week's break of it. She's not performing anywhere near here. We currently have tickets in Perth for end of June and if Sydney doesn't work out we'll do that. Although flights are expensive and flight times not great. Would go for 2 nights if Perth.
There are lots of serviced apartments in central Sydney which you can rent for a night or a week or longer. I've used several, most often The York Apartments, which is in an extremely handy location - right near the Rocks, almost on top of Wynyard station, short walk down to Circular Quay for the ferries, Opera House etc. They have studios up to 3-bed apartments, I think, with living rooms, full kitchen, washing machine etc.
Or if you search the usual travel websites, there are loads of other apartment-hotels in Sydney - it seems to be a much more common thing there than in the UK. Cheaper than a hotel, much easier if you are travelling with family, and July is off season, so you might be able to get a decent deal.