I was under the impression that if you made a journey after 12 months, it would be refunded automatically then. The credit online shows the amount actually on the card as far as TfL know, not how much you could hypothetically have next time you touch in/out.
If you don't touch in soon after the 12 months (I don't remember the actual time period), then you won't get the £5 added immediately. Instead, the system must detect your card has been used, realise it never gave you the £5, process a £5 refund, then wait for you to make another journey to actually update the card's balance.
If you don't make another journey in the few days after the first journey, the credit refund will "time out" and you'll have to start again (i.e., make another journey to make the system realise it still needs to refund you, etc.).
I'm sure that
@MikeWh will come along and correct me (and/or others) if needed, as the expert on all things Oyster!
Edit: would have been easier to consult MikeWh's website, wouldn't it!
https://oysterfares.com/information-pages/topping-up/
FUL is the name of the system used to transfer topups, refunds and products to Oyster cards when the request is generated remotely from the card.
The main list is sent to every station, tramstop and bus. The amount of topup/refund, or travelcard/bus pass will be added as soon as the Oyster card is touched on a reader as part of a journey (can be entry, exit or interchange). Items remain on the main list for three whole days, plus the hours between request and midnight when the customer orders the topup or product. At the end of that time the item is deleted from the main list.
[...]
If it was an automatically generated adjustment or refund then the item moves to the reserve list. This is because TfL can’t be certain how the item could be refunded.
[...]
The reserve list is held on the central database and is checked every time a card touch is received by the central system. Once a match has been made the item is transferred back to the main list as a new request with a new 3-and-a-bit day duration. In most cases this means that the amount will be added on the second touch (either touch out from a train or touch on a second bus journey). Items remain on the reserve list for six months from the initial creation date. After that time they will no longer be automatically re-queued to the main list, but details can be accessed by customer services should the customer decide to request the refund at a later date.
The two main uses of the reserve list are: [...] (b) refunds of the £5 card fee after one year. In the case of the card fee the request is actually placed on the reserve list first because there is no guarantee that the card is still in regular use.
In a nutshell, after 12 months of having the Oyster, the card number and the £5 refund is placed on the reserve Faster Universal Load list, where it will remain for the next 6 months.
If you touch in within this 12-18 month period, your card number and the £5 will be moved to the main list, which is sent to every Oyster validator. When you next touch in/out after a validator has updated its main list, the card will be credited the £5.
If you don't make a journey within this 12-18 month period, the £5 credit won't be re-added unless you contact customer services to ask for it, then they can manually reinstate it, and you'll have another 6 months to collect the credit.
