AMEX has given me a friend-invite link with exceptionally large cashback: 34000 points for 3000 spend in the first 3 months.
Link: americanexpress.com/en-gb/referral/sERGEs3eAy?XLINK=MYCP "Your friend will receive 34,000 Membership Rewards points when they apply for the American Express® Preferred Rewards Gold Credit Card, are approved and spend £3,000 in their first 3 months of Cardmembership."
Now, about this card: It has a stupid-high 60% APR and stupid high fee of £140 per year, but waived for the first year. So, you need to pay in full and you need to cancel before the year 2 starts. That's it. And you bag 5.5% cashback on all your spend if you spend £3000 in first 3 months. It's easy to spend, just buy Tesco giftcards in store , or other giftcards via TopGiftCards. To get £272 cashback, you convert 34000 points to 34000 Avios, and then you convert Avios to Nectar at a rate 400 nectar for 250 avios. This way, you arrive at £272 cashback to spend in Argos/Sainsburys or on ebay.