I second the idea of the website, it's made the world of difference for my interviews and parent's interest because they see it all before they meet us. You need lots of fun, action shots as well as the creative aspect in your pictures and you must figure out your niche and what you can offer that your neighbour does not.
There are a whole LOT of home daycares in London and some areas are really saturated. I'm near downtown and there are tons of office workers. Depending on your area of the city can you advertise at the factories, the hospitals, the university or college to find people? Good luck.