I've just been making the same enquiries and my letting agent also said that the tenant can renew the lease after the 1st year.Also,you cannot put the rent up till end of the second year.
You may find that you will find a investor who is happy to buy your studio with a tenant.
You could always contact your tenant and ask her politely if she could move out.Maybe even offer her a small financial incentive like 2/3 months rent back.