I've done this this year.
I decided to get out of London early Yr 5. Literally decided overnight it was the right thing. I managed to get out to the town I planned moving to and saw a couple of secondary schools. Check the admissions criteria stringently including asking for any planned changes. The one I wanted changed their admission code a year ago and it has huge implications for the address I needed to move to.
I then looked for and got a job. I left DC in London school and commuted outwards.
I kept enquiringly for primary places and I found one I was content with for older DC y5 and moved DC with a day notice to the London school. So two of us commuted 
The other stayed in London!
I also kept hunting for a rental in new town.
Once I'd got a rental sorted, I moved younger DC to new (different) school and three of us commuted. A month later we moved house.
I'm about to take now y6 DC to look at the school I already selected for an open day and the CAF form goes in from the rental address late October.
I did try to sell London house but market is flat so it's currently rented out.
There is no way I am playing any systems or games. I have an owned property 40 miles away. (I have two actually!) I have moved lock stock and barrel to a new town where DC attend primary.
I will rent for another year and try to sell London again before finalising my move completely.
DC should get the secondary school I want. Younger DC should then get a sibling link in a few years as long as I only move within a certain distance of the rental original address.
Your DH dream is possible! You just need to do a lot of planning. A lot! Plus have a really good understanding of admission rules and preferably move to an area where there is some movement at primary level. I have sacrificed a lot of my time though driving across town endlessly between two schools and work.
Older DC has made new friends from mid Y5. I doubt any of them will go to (my choice) secondary as they live on the other side of town.
SATS and friends were of zero importance to me in making my choices.