@Edent the Office for National Statistics, when they do surveys, give you one of these vouchers -- https://www.pluxee.uk/products/evouchers/ -- which the recipient can then choose from a bunch of different stores and restaurants and such. I turned mine into an M&S one one time and had a lovely dinner No idea whether you have to buy 10,000 at a time or something, mind, or whether it'd work for you, but I found it useful, and the ONS presumably (hopefully?) did at least some due diligence on them being OK
