You say other colleagues have been approached by her asking to lie on her behalf, can they not stand up for you if it goes any further ? there obviously good friends otherwise they wouldnt of mentioned it to your right, you could ask them all to write a small statement saying she has aproached them asking them to lie and it will all be ignored. Its usually the chubby/obese/fat ones that do things like this as there never wanted by the oposite sex so they make shit up to make themself feel wanted/better. Ive been at recieving end when i was 19 but i got face on when she squared up to me so i headbutt her :/ she got done for asult as she started it too !! ha