do i have to receive notice in writing from tenants to end tenancy as in agreement

Other

Tenants have give verbal notice to end tenancy in a months time. As tenants have not sent us this is writing do i :-

* write to them confirming conversation and their intention to end tenancy, (don't want it to seem that i have pushed them into anything!!!)or
* just ask them to confirm notice to quit in writing (English second language,not sure how easy this would be for them, hence though 1st option would be best - also they may choose not to)

Any other suggestions would be appreciated, they gave notice on Thursday 30th Jan 2014 to leave at the end of February 2014.