Hello freelance glad to see it is going ok with your client, albeit not well paid.
I think there are 2 things you want to change - a) the hours you are having to do and the b) pay you are receiving from this client. Is increasing the pay going to be enough to make working all hours seem worth it? ie is this just about the money...?
If yes, then I'd approach them at a sensible point (maybe not just before Xmas for your DC's present sake :) just in case it goes wrong) and do as strong suggests just be honest and outline what you are looking for. A copywriter I sometimes use put her prices up from £20 to £30 ph and I still paid as I needed her and valued her work. If they say no you are no worse off. If they are happy with you (and realise what a bargain you are!) I doubt it will make them dump you.
If no, then maybe you need to take a step back and think about the sort of "business" you want in 2014 if you haven't already. An approach could be (with made up figs):
- I want to bring home £20,000, so I need to earn £24,000 (assuming 20% aside for tax & NI)
- I have 20 hours a week to work (excluding evenings). So removing 5 hours for admin/business development I therefore have 15 hours to deliver work.
- For 46 weeks of the year (holiday/covering DC school hols too if needbe)
So therefore to earn £24,000 over 690 hours = £35 per hour.
So, can your current client help with this? If not, then maybe you need to be looking for new clients to replace them. There is something to be said about not just having the 1 client including IR35 en.wikipedia.org/wiki/IR35 and spreading the risk.
I know you had a very unfortunate experience with that potential client messing you about but you don't know what other potential great clients are out there unless you look etc..
I have found there is always a bit of up and down on the hours with freelancing. However you shouldn't be working every evening...Are you able to "give yourself permission" not to work? I know I find that difficult.
Finally, you should be really proud of what you have achieved so far. It takes guts to start up alone and on many levels you are making it work. 