Honestly, if I was doing it all again, I wouldn't bother with an inverter at all. I'd run all my regular stuff off 12v (laptops, tv, fridge etc). Don't use electricity to run anything which produces heat (so use the hob/grill for kettle and toast). I'd have a generator for the occassions when I really need to run 240v (power tools, washing machine), and that way I'd have another way to charge my batteries in case of engine issues. A reasonable quality genny is cheaper (for the same power) than a reasonable quality inverter. Doing it this was will also put less strain of your batteries, so they'll last longer, saving you even more money.
To the OP, it's not until you go cruising permanently, that you'll realise just how important it is to minimise electricity consumption. Until you do, repeatedly wrecked batteries will be the order of the day. Also, get solar panels fitted.