Heathrow airport giftcard?

[workstealssleep]

I need to buy a gift card for a family leaving the country for Christmas. I want them to be able to treat themselves at Heathrow before their evening flight.
Does anyone know if a Lifestyle giftcard would do? Does Heathrow have enough of the shops and restaurants? Or is there a better way?
I am imagining them all having a glass of bubby/fancy drink, or maybe just buying a book or mgazine if they would prefer.
I have £50.

Will they definitely have time to use it? Some people don't have loads of time to leisurely spend in the airport or prefer to be sitting ready to board

Could you put the money in a card with a note to treat themselves to a glass of fizz at the airport?

Thank you for the suggestions.
I would have thought they would have plenty of time. They are not frequent flyers.
I didn't want to send cash in the post. I guess I was thinking this is a back up if they don't have time, they could spend it on the way back/once home.
Does anyone know if there are definitely shops and places at Heathrow that are on this card? I don't know Heathrow.

I wouldn't. Too niche if not used. But a coffee shop voucher might suit.

What about treating them to the lounge at the airport?

The airport branches of chains are often excluded from vouchers on the t&c. They may also have booked a lounge and not want to or have time to use a voucher.

You'd be much better to transfer cash and say 'treat yourself at the airport.'

Thank you everyone