rent increase

Tenancy Types and Management

I have a tenant whose tenancy commenced on the 4/3/06 with a monthly rent of £375 and, on the same date, i served a 21(1)(B).

i wrote to the tenant, on the 12th March 2007, to inform her that, with effect from the 4th April 2007, the rent was to be increased by £15 per month to £390.

The tenant has refused the increase, i have told her it is not negotiable as £390 is market rent and therefore asked her for her notice to vacate.

If she does not provide this, given that i served the 21(1)(B), am i obliged to give her any notice? If so, the tenant currently corresponds by e.mail, can i provide notice by e.mail?

If she does agree to leave, can i ask her to vacate more or less immediately?

I await your reply.

Thank you,

Martin