Husband and I are travelling to Australia next March for about a 12 week holiday. To help we are both 59 years old. Over that 12 week period we will be staying in Sydney for around 5 weeks - at different times. Does anyone know of decent serviced studios that do not cost too much. We are looking for something around £250 per week. Any help would be appreciated. Thanks.

Our Welsh mate, Mucky, speaks well of Waldorf apartments.

The rates look within your range.
Have a look here: http://www.waldorf.com.au/reservations_contact.html

We stayed at the Oaks Maestri Tower in Sussex street, we had a one bedroom apartment which cost $200 pn - I think they have studio apartments which would be cheaper. The complex had a swimming pool/spa/sauna/gym, with good security. The Oaks is within very easy walking distance to Darling Harbour, Central Station, Paddys Market we also walked from their into Circular Quay a long walk but very comfortable. There is a convenience store across the road, along with many restaurants and fast food stores nearby.
Before deciding on any accommodation I aways check the reviews on www.tripadvisor.com

Try Quay West as it is close to the most beautiful spot, the harbour. Ring them as they may be able to give you special long-term rates. Ask for a view of the harbour.
www.mirvachotels.com

The original poster said £250 per WEEK, not per night. That's about AUD 630. That won't get you two nights at Quay West with a harbour view. The Waldorf is in range, though.