Home fee for a gap year student

I am a British citizen, I have lived in England since the age of 3. I finished my A level in June 2023 and I have been travelling overseas on my gap year since Aug 2023. I was planning to return to UK this Sept, although I haven't booked the return flight yet.

The university, which I am going to attend late this Sept, is asking me for proof of residency to determine if I need to pay for home fee or overseas student fee. They have asked me if I am going to be back in the UK on 1st of Sept.

My question is, do I need to be back in the UK on 1st of Sept this year, in order to be eligible for home fee as an undergraduate student? My course won't start until late Sept and the price of flight tickets in Aug is much more higher than Sept ones.

Many thanks.