The pre-authorization is the maximum we'd take if you used the full reserved amount. In practice, we only capture the value of the energy you actually used — so if you only spent £12 on a session, only £12 is captured against the £50 hold. The rest of the hold is released by your bank, typically within 3–5 working days. The figure on your statement should match the kWh delivered × the per-kWh price for the tariff you used.