How old are they? You don't necessarily have to mirror the National Curriculum and make them do worksheets etc. As you've discovered, that is tedious and it's no wonder children don't enjoy it. If they are whining, it isn't right for them. Schools have little choice but to make kids do the same thing whether or not it is interesting to them, and to make them produce written "work" because the teacher doesn't have time for proper individual observations and discussions with dozens of children to discover what they understand. But we don't have those constraints.
You could adopt a broader, more flexible approach as most British home educators do, and take a break from school-style learning. Obviously if the kids are returning to school in the UK soon, you'll want to keep up with whatever core skills you think they need to work on so they can slot back into class. You mentioned maths, which you could do in a more hands-on way. Measure up to make dolls' clothes, play video games in which you need to know what you can afford to buy with your virtual money, spend money in the shops, estimate how much the chocolate bar you've just bought is costing you in pounds, play card games, discuss graphs showing how numbers of an endangered butterfly species have changed over the years. (What does a quarter of a pizza look like? Could you divide it into quarters using different shapes, such as parallel cuts instead of cutting through the middle? We do that because some of us like the crusts more than others, but we think we should all have an equal amount.)
Maths is all around you. That's why it's important and is the reason schools push it so hard. But schools don't have ready access to all the practical situations children naturally encounter in their daily lives, so schools have to cover maths in a more artificial way, which children often find pointless and hard to engage with. If your kids have access to their dolls' clothes, video games, shops, cards, and pizzas then they can just learn these ideas directly. It's very effective. My eldest never did any formal maths until their teens, when they started from scratch and worked through the GCSE curriculum in one year. But they didn't have much catching up to do, because life had presented mathematical ideas naturally all along the way.
Aside from that, why not take advantage of your circumstances and check out the history and geography of the local area, maybe pick up what you can of the language, see how the offerings on TV stack up with what you are used to, talk to people and discuss cultural differences, go out to look at nature and compare the plants and animals with what you're familiar with back home?