Hi, I'm glad you've been enjoying educating your kids at home!
If you withdraw your children from school, you won't get any help provided by the government, but likewise there's nobody telling you what you have to do and when and how. So it's more effort to figure out what your children need and provide it to them, but at the same time you are completely free to choose what suits them best.
If you like the simplicity of having it all laid out for you as it is now, you could buy a ready-made curriculum from a private provider. Some companies do sell a complete package like you are now getting from the school, but that is not so popular in the UK anyway. Many parents who use a curriculum prefer the "pick-and-mix" approach for the different subjects where, for example, you might buy a maths curriculum from one provider, science from another, and put together history yourself.
Many parents are inclined to buy in a lot of support when they start home educating, either because they assume education has to be done that way or because they feel it would be too difficult to put something together themselves. Over time, there tends to be a drift toward more informal learning as families see that a ready-made curriculum might be too rigid for their kids. Some parents do follow a curriculum with set lessons in the long run because they prefer to have all the planning done for them.
There are many, many different ways to home educate. My two (now aged 13 and 20) do "autonomous education" where they choose for themselves what, when and how to learn. Usually this is totally informal and doesn't involve textbooks, but there have been times when they requested more formal "lessons". For example my eldest had a tutor for a musical instrument, attended German lessons, and used a maths book to prepare for GCSEs. But before that she just picked up maths by handling money, reading graphs in the newspaper, doing calculations for DIY projects and so on. It may surprise you to discover how much kids can learn informally. When she tried school for a short while aged ten she wasn't behind, and she had no trouble getting through the GCSE curriculum in one year when she knuckled down to that.
Most home educators recommend that you don't commit too much money at the beginning but instead take time to figure out what you want to use and keep flexible because you will want to make changes as you go. Another common recommendation is to take a complete break from all adult-directed learning for at least a few months while your kids relax and find out what really interests them. During this time let them play, read and do hobbies - whatever they want. You'll be able to see better what they need and can experiment with gradually introducing things. There's no hurry because when you get stuck in with materials which suit them, and they have one-to-one attention from you, they cover so much ground so fast. Especially at this age, you'll probably find that you need no more than an hour or two a day at most.