I got mine by posting on my local gumtree - she did a deep clean and now does regular cleaning for me. But do a list first of what you want doing. You could also try posting this on your local mumsnet group.
I used karma kleaners when i was pregnant, couldn't really justify a regular cleaner so used karma to do light cleans to help me catch up with housework. They specify a three hour minimum clean which worked out to £36. Bargain