Possible partial payment

Rent Arrears

We have a shared house with four students who each signed the same agreement for the property.

One of the students is now 5 days later with his rent. After contacting him two days ago he stated that he would pay in a few weeks.

We sent him a warning letter for late payment of rent. As of today he has sent an email explaining his situation of financial difficulties, but this was written in sarcastic terms. He says he may be able to pay part payment by this weekend.

So my question is: if part payment is made does this warning letter still stand for Aprils rent if he does not pay on time again or at all as I can not see his financial status changing in a month, can we still follow legal actions as if he had not make payment for 2 months or do we have to start again with a warning letter.

thanks