For the first transaction the payout from Stripe will be made in 7 calendar days.

For every subsequent transaction the payout will be 5 calendar days.

Instant Payouts
With Instant Payouts, Users can access their Stripe balances immediately following a successful charge. You can request an Instant Payout any day or time, including weekends and holidays, and funds typically settle in the associated payout account within 30 minutes. New Stripe users aren’t immediately eligible for Instant Payouts.

Accounts in good standing will typically get access after processing on Stripe for a minimum of 60 days and £5,000 in volume.

In order to be eligible you will need to meet Stripe's criteria:
https://support.stripe.com/questions/instant-payouts-eligibility

And to check if you are eligible please click this link once you are logged in to Stripe:
https://dashboard.stripe.com/payouts/instant_payouts_eligibility

More information from Stripe here.
https://docs.stripe.com/payouts/instant-payouts#eligibility-and-daily-volume-limits