Sugababes singer Keisha Buchanan has hit back at social media trolls who’ve criticised her spot in this year’s BBC Strictly Christmas special due to her experience in a girl band. Buchanan is one of six celebrities who’ve signed up to take to the dancefloor for the one-off festive special. She’ll be dancing with Gorka Marquez who was booted off the main series this year early on alongside Nikita Kanda. Dan Snow, Danny Cipriani, Sally Nugent, Jamie Borthwick and Tillie Amartey complete the line-up alongside the Sugababes singer. Speaking about her reasons for signing up for the show, she admitt…