How about joining the 'bank' at your local hospital and work as a healthcare assistant, not necessarily in maternity. You would be able to work as much or little as you want. If the HCA is only able to work for a few hrs then the bank sometimes allows the HCA to work part of a shift. Its probably worth giving them a call. Someone I trained with worked a nightshift a week at a nursing home.

I worked as a barmaid throughout my training. I worked at several different venues on a casual emergency cover basis, so if someone phoned in sick I would get a call asking if I was available for work. This worked really well for me.

What about delivering leaflets or being a party host for a company such as Virgin Vie or Ann Summers?