Fibre Upgrade query

[#1]

I'm currently on the PlusNet Value package and my billing date is the 9th, my fibre extra install date is on the 11 Sept, two days after my new billing period starts.
As its a new contract will i go straight on to the 250Gb allowance or stay on the 10Gb for another month - how does this all work? Staying on 10Gb for another month with fibre would just be a nightmare I dont want to contemplate tbh!
Cheers

[#2]

I can see your appointment is confirmed for the 11th September. When your fibre has been installed then you be on the 250GB usage from that date(11th September).
I hope this helps.
Chris

[#3]

Thanks for the confirmation