John,
Sounds about the same as my pricing structure.
The way I see it, I can do a 3 bed semi in 3 hours, so £100 for 3 hours work is a pretty good return in my opinion. If I could do one 3 bed and a smaller job most days I would be more than happy with that.
Just out of interest, how often do you get jobs for a whole house? I find those jobs very few and far between at the moment.