People most often lose a bonus by being ineligible before they start. The usual reason is that the bank they’re switching to shares a group with one they already use, or one they took a bonus from years ago.
The two things banks check
The first is whether you already hold an account with them. Most offers are for new customers, and some count anyone who held an account on a particular date. HSBC looks back to 2023 and NatWest to a date in 2026, and those dates move.
The second is whether you have had a switch bonus from the group before. That usually rules you out for good.
Only you know which bonuses you have had. No app can look it up, and a wrong answer produces a roadmap that can’t pay.
What we do about it
The app asks which banks you hold and which bonuses you have taken, then applies the group rules for you. It picks the better of two offers inside one group and lets you swap to the other if its pay-in is easier. Where a bank has a date-based rule it can’t check, it tells you what to confirm before you do the work.