Partial Payment of rent

Rent Arrears

My tenant claims housing benefit and has been consistently late with her payments. She is on a 1 year AST expiring 31.12.10 and I have served a section 21b as standard. She tends to pay in dribs and drabs ie £25 here £120 there. At present she is £155 overdue from 01.06.10 and obviously 01.07.10 is rent day again. She has advised me she has asked the council to start paying me directly. My question is: Because she stills owes some of the rent from 01.06.10 and this constitutes a partial payment if no rent is paid on 01.07.10 will this make her 8 weeks overdue as the 01.06.10 is only partially paid. Or does the fact that she has made a partial payment constitute payment? I ask because I want to contact the council and advise the rent is 8 weeks late so as to ensure the benefit comes directly to me henceforth and bot just take her word for it.

Thanks in advance RLA.