They are suing after they rejected LDR's offer of 40 percent of the proceeds. The back to back comparison on 6music this morning certainly demonstrated that the two songs sound like two parts of the same piece almost to the point of being the same. The whole vibe of Creep was there and when Creep was faded in, there was little doubt as to the similarities.
I reckon someone's pulling a fast one. That or everyone around this artist lives in a Radiohead-free bubble. I don't think it is a deliberate rip-off but I don't think the offer of a 40 percent share of the LDR royalties is adequate either. If the offer is less than fifty percent towards Creep's publishers, it makes it look like she's taking the wee wee.