Too late now, but never, ever rent a place out without a tenancy agreement in place. Even when you think everything is going to be fine, there will be niggles, miscommunications, etc and the potential for fallings out.
If they agreed to paint the kitchen ceiling and haven't done, can't you just remind them of that and ask them to get it done? See what their response is before you do anything else. If they said they would do it and now say they haven't the time or the energy, remind they moved in early saying they would do it and suggest they get a decorator in to paint it.
As for the work your DH has been doing in one of the bathrooms, that's wear and tear I'm afraid.
I would suggest you moot the idea of putting things onto a proper, documented footing with an AST - for their protection and yours - and broach the subject of the rent at the same time if you need to put it up to cover your costs. But, do bear in mind that even one month without a tenant paying you rent can be costly. So don't cut your nose off to spite your face.
With the best will in the world, even the best tenants won't do things as you would in what was once your home. You have to disengage to a degree and not take it so personally. If you don't communicate clearly as to what their obligations are, inspect regularly, etc then you cannot expect them just to do things. Even when things are in black and white in the terms of a tenancy agreement, they don't ever always read them, but at least you can rely on those Ts and Cs when the cost to deal something falls to you.