There are no government packs, though the National Curriculum is freely available online if you want to use it as a guide. As morethan said, government and other agencies tend to have quite out of date information on resources, it's just not their area. I've been given sites with gushing recommendations that haven't been in use for years.
Amazon is a good place to get lost down the rabbit hole, but for finding curriculums you don't know about. Currclick.com, thecurriculumchoice, freelyeducate.com are good starting off points, I find, though often have a US tilt to them which is fine for some subjects though obviously not others. That is part of a larger problem of finding systematic programmes as most focused on home education are from the US and the British ones tend to be more aimed at schools and need to be adapted for home use. I tend to break it down subject by subject.
For maths, I recommend CIMT, which goes from reception to A-levels, and has the sort of systematic programme you sound like you are looking for. There are free lesson plans on the websites as well as the work pages (though I recommend buying the books, good quality and inexpensive and no worries about printer settings for the measurement sections). There is a yahoo CIMT group that will give the password access for the secondary answer sheets and tests (primary is all open I believe). We've really enjoyed and had great progress with it.
We use piperbooks for early reading, another systematic programme, they have small decodeable books. Some people use them from the start, others use them after single-letter phonics instruction and writing to build up skills, confidence, and to avoid guessing habits.
Science - msnucleus.org/curriculum/curriculum.html, thehappyscientist.com/next-generation-science-standards give suitable tick boxes that you call fill in as you or your kids want.
History: General historical reading is a good start, for middle/latter years worldhistoryforusall.sdsu.edu/ is a solid spine
These are obviously just mine, there are really a lot of options to pick from. Essentially, consider what you want to teach and explore your options to find a fit for you and yours. You may prefer the systematic approach or finding a grounding may put you in a different direction.