When I took my Y8 daughter out of school I followed the lesson plans on the government site here. It gave me confidence she was covering what she would have been doing at school. She's now Y9 and we're working towards GCSEs (she takes Biology, Geography and the rest of Foundation Maths in the summer) so we've dropped History for the time being. The LA advisor said we didn't need to cover everything at once at this stage, and as she decided to go down the GCSE route, we thought we'd tackle a few at a time.
For maths, I really liked the WHSmith Revise Maths series - there's 2 books for Y7, 2 for Y8 and 2 for Y9. From there we moved on to the CGP revision book for GCSE maths foundation level and we've now moved on to higher. It all sounds very quick - it was! She came out of school very confused in maths and really only at Y6 level, in only a year she's taking GCSE. It's astounding what you can do on a one-to-one!
My youngest is Y6 and I think, having got a bit more experience and a lot more confidence(!), that I won't be so rigid or follow the DFES site for her when she is secondary age next year. So far we've just done topics in History or Geography she's fancied doing (eg, WWII, Victorians, Weather, Rainforests, Rivers, Erosion)and same in science, so actually I don't see why suddenly I have to change that in September just because she is secondary age and it's a more traditionally primary way of doing it. So, I'll ask her what she wants to learn about, and we'll go with it. In History we quite fancy reading a book called "Our Island Story" which is a very old fashioned history book that some other HE ers have used and tells history like a story, in chronological order. It only goes up to 1900s, I believe, but she thinks she might enjoy it as she is very story orientated.
I think you could continue to go with the flow, but maybe look at some of the things you might like to learn with a historical or geographical bent and go from there. I think it's easy to get really scared over secondary level, but I've relaxed enormously. How much of what they learn in KS3 (11-14 years) do they actually need? How much does the average school child remember? My guess is very little. So I'd go with what you all enjoy and not worry too much about what you "should" be covering.