UK Landlord Forum / Life

I have a 6 bed HMO which has recently been let out to a group of first year students in September 2013. All tenants paid 1 months rent up front plus a months rent as a deposit.

I carried out credit checks on the tenants guarantors and all were fine except one who had CCJ's. I asked this tenant to provide another guarantor although I was told the only other person he could use was away on business until November. Due to only finishing the renovation of the property in September, the academic term about to start and the tenancy due to commence in 3 days I decided to give him the benefit of the doubt.

Octobers rent was not paid. I tried to phone him several times although kept getting his voice-mail. I contacted another tenant and was told he had lost his phone.. I continued to frustratingly contact this tenant via the other tenants although he was rarely with them and he would often chose to ignore my requests to return my calls. I have also tried contacting his temporary guarantor over the last few weeks however I am just get false promises that I should receive the money in the next few days..

I sent a letter on the 7th day his rent was overdue advising that he will be £25 if I fail to receive payment in the next 7 days.
I sent another letter on the 17th day after his rent was due advising that if I have not received payment within the next 7 days I will visit the property to discuss his unpaid rent on a set day and time (giving him plenty of notice in advance).
When I visited the property all the tenants were there except for the one not paying.
I then contacted all of the other guarantors to make them aware of the situation and that he hadn't paid.
I have been in close talks with the universities accommodation office and they have met with the tenant with his course leader and offered him cheaper accommodation in halls although he refuses to leave.
The other tenants have even written him a joint letter asking him to leave by today although he still refuses to go. I have also been chasing him for another guarantor which he is reluctant to do, although I have given him a deadline of Sunday to provide a suitable guarantor else he will be asked to leave. I have also been advised that he is smoking in his room and has advertised a house party on Facebook against the wishes of the other tenants.
All the other tenants and guarantors want him out although I am unsure if we legally can throw him out with it being a joint tenancy. The other guarantors are even threatening to move their children out of the property if he stays. The university has suggested that I write a letter to him on Monday giving him until the end of the week to move out due to not providing a suitable guarantor, paying his rent on time and failing to meet me and return my calls. At the end of the week I would change the locks and give him his belongings on his return to the house. Maybe arranging with the uni to take him to student halls. Am I legally allowed to do this?

Also having spoken to the guarantors and other tenants, even if he pays his rent next week and finds a suitable guarantor they are not happy for him to stay in the property as the trust is no longer there.

Any advise would be much appreciated.

Thank you in advance.