MONEY INFO EDIT how can I get her to move out?!?! EDIT

I'm 38 and have a 20 year old daughter. She's 21 soon. In 2015 she moved away with work and recently moved back home in December 2016. Whilst she was working away she didn't save any money up!! I know she was on minimum wage and paid £80 a week for her accommodation but surely she could've saved something!! So anyways she stopped working where she was (she sustained an injury that stopped her dancing and that's what she did as a job...) and she moved back in here but now she's saying she can't afford to move back out. We are in England and I know for a fact she wants to like in Scotland (well the boarders) as her boyfriend and friends are up there. She is currently on universal credit (like jobseekers/ benifits) and gets £251 a month. She then pays me £80 a month to live here then gets her own food ect. How can I make her move out??? She's almost 21.... She shouldn't still be at home,. How can I make sure she can afford it? I've seen some flats for £450 a month but obviously that's out of her budget too. It's not that I don't like here here but it's a 3 bedroom house and I have 2 other daughters (4 and 7) who would like their own rooms... She has been looking for jobs, I've personally seen her apply for atleast 100 in the past month (no lie!) but she's getting nowhere. As well as this I also know where she's spending her money. She geys £251 and gives £80 to me for rent, pays about £50 for food, £40 travelling to Scotland 5 days of the month to see her partner and £80 on driving lessons (4 a month) which leaves her with nothing. She's only got £200 saved