Moving house and secondary admissions

[SchnitzelVonKrumm]

Need some advice please. After renting for much longer than we expected while looking, we have had an offer accepted on a house. It needs a lot of work, so even if everything proceeds smoothly, we won't be able to move in for at least six months.
My eldest child needs to apply for secondary school in September. Our current house is comfortably within catchment, whereas the new house is right on the edge of the catchment area (would have got in for four of the last five years, but it was outside one year).
The timescale for purchase and renovation means we will almost certainly be living here when the admissions deadline passes on October 31, which should ensure my child gets a place at the school. Do we then have to wait to move until places are allocated in the spring or could we move within that period without possibly jeopardising her place?

You need to talk to your LA. Some will insist on using the address of the house once you have purchased it even though you haven't actually moved. Others will allow you to use the rented address on your application. Each LA has its own rules on what happens if you move house part way through the process.

There seems to be huge amounts of temporary renting to get into this school (one of the reasons it's so hard to buy a house in catchment!) so I think they must take addresses at face value but I'll ask them.
The admissions booklet says the address must be where your child was living on October 31. It gives advice for people moving into the catchment area after that but doesn't define permanent address etc.

We were in a similar situation a number of years back (renting long-term at the deadline date but planning to move to a slightly further away location once we finally closed a house, which happened 6 months later). We applied using our rental address as it was our bona fide address at the time (had been there three years while we tried to cobble together a deposit). The school was fine with that.