Geri Horner will no doubt have delighted fans after she posted a heartfelt tribute to them in celebration of a very special anniversary.The former Spice Girls star took to her Instagram Stories on Wednesday, where she shared a link to the group's official account.SEE: Geri Horner shares rare photo of her mum - and she looks like a famous Hollywood actress!The mum-of-two wrote: "To our die-hard and loyal fans: without you, there is no us – sending endless love and gratitude.Whoever you are,