Hi Green,
You seem to be doing lots all in different areas. Possibly buying domestic work, which if legit is a good way to expand.
Now onto other services.
Well, my opinion is that yes you have the ideal market already as they are residential. As you say you already clean their house so they know you.
I think it would work very well. Infact I know it would. I have friends that do this. They earn reasonable amounts. And as an add on service I think it will go together.
My freinds have now expanding and actually have dog cages in there gardens to look after the dogs when people go on holiday. They get alot of bookings.
Your market need to be the more upper class, not the council estate that has had a riot on, i.e. moss side. Try leafleting the posher larger houses.
I think alot will be on for the dog walking and pet side.
Its like anything market it well, and aim at the correct clientel and you should be away.
Best of luck with it all
Dave