Hurry to use old Nando's loyalty cards

Nando's customers with an old loyalty card must use it or exchange it by 30 June or lose any freebies they've earned.
The spicy chicken restaurant chain introduced a new card in April, meaning the old version will soon be defunct.
With both the new and old cards, staff add a stamp for each eligible purchase. When you hit a certain number of stamps, you get a free dish.
What are my options?
If you've got an old card, you can either use it by 30 June or transfer the stamps to a new card. From 1 July, any stamps earned on the old card are useless.
If you've got the new card, nothing changes.
Which card is which?
The first image below is the old card, the second is the new card.

How do you earn stamps?
Each time you spend £6 or more, you receive a stamp (one per person, per visit, per day).
How can you spend stamps?
On both cards:
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3 stamps = a free 1/4 chicken (or vegetarian alternative)
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6 stamps = a free 1/2 chicken (or vegetarian alternative)
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10 stamps = free whole chicken (or vegetarian alternative)
On the old card, technically speaking, customers must claim the three-stamp and six-stamp reward on the same day they get the stamp. However, some customers have reported being able to claim their freebie at any time once they've hit the threshold.
But the new card is more flexible as customers can claim their reward at any point, once eligible.