Look at Moneysavingexpert.com. The money makeover walks you through setting a budget including all those annual and irregular expenses that will be taking up some of your £900 that appears to be spare, but much of it might not be - some of it will go on things like car repairs, insurance, Christmas, school uniforms etc etc.
You need to include these sorts of things in your budget and put money aside for them before spending on things like takeaways, coffees or days out.
MSE will also signpost you to ways of increasing your income, cutting the cost of broadband, phones etc etc, increasing the money available to get out of debt and then save/spend.
Agree that adding the debt to your mortgage or getting a consolidation loan is probably a very bad idea so its quite irresponsible for people to suggest that when they don't have a full picture of your budget and you don't know what you can properly afford or whether its the best solution, which it rarely is.
If you keep plugging away, tackling the debt with the highest interest rate first, you might become eligible for a 0% balance transfer in time. For now, transfer the maximum you can to the £800 card.
For all credit cards, if you pay even £1 above the minimum payment, it removes the minimum payment marker from your credit file so looks a little better to lenders. Then every few months use the MSE eligibility calculator to find and apply for a new balance transfer offer as you may be able to get a bit more on the 0% deals as your finances improve.
For takeaway avoidance, plan for the CBA to cook nights with things like pizza in the freezer, supermarket meal deals - choose carefully and a £10-15 curry deal for 2 will feed the 3 of you. Or have something batch cooked in the freezer.
Also have the teens cooking at least one night a week each, or doing two nights when they both share the cooking.
Another quick easy cost effective weeknight dinner I like is spaghetti bolognese with a jar of Heinz pasta sauce, which is quite nice, not UPF and often on offer. I use a can of green lentils, but you could also use pork or turkey mince which is much cheaper than beef. Add some grated parmesan or strong cheddar, a bag of salad leaves, punnet of cherry tomatoes and possibly ready made garlic bread if your teens are bigger eaters.