BDCS no, of course you don't need to have built in to your site. I'm just interested to find out more about people with sites that might have thought about it, as well as understanding what considerations were made at the time of building the site.
So far I have found one cleaner in the country that has direct booking facilities on their web site, and he swears by it. Obviously this suits his business and wouldn't suit everyone. But I'm personally interested in those that might have thought about it and not gone for it, I expect likely due to cost involved.
My personal project that I'm currently working on is to provide this booking functionality for cleaners through a web site. I'm obviously very keen to get views good and bad on this type of function.