Low Cost Keyless Entry and Exit required for internal doors? You need the Borg BL2021 Digital Double Sided Back to Back Lock
The Borg BL2021 is a complete mechanical lock with a key pad on both the entry and exit sides of the door giving access to authorised personnel only. Over 8000 combinations ensure secure access control.
Suitable for standard thickness internal wooden doors the keypad on each side means a code is required both for entry and exit.
See https://www.safesafe.co.uk/safes-2/borg-bl2021-digital-double-sided-back-to-back-lock/ for the lowest price.