UK Landlord Forum / Life

Hi.
Just wondering if anyone can help me out here?
About 6 or 7 years ago my partner at the time took out a tenancy agreement on a flat and i was with him. At the time the landlord asked for a reference from his previous landlord and my then partner signed his lease. The landlord then asked me to sign something at the bottom of the contract stating that i was acting as some kind of reference. I signed and named the letter and put a false address on it just in case anything happened as i didnt want any responsibility for the flat as it didnt really have nothing to do with me. Anyway i know the person who's address i put on the letter and in the last week they have recieved a letter addressed to me stating that my ex has left the flat with an arrears of £960 and in a bad state and if i know the whereabouts of this person. Now I havent seen this person for about 4 years and wouldnt like to ever see them again if im being honest so where does this leave me. Should i just ignore the letter or have i got some kind of legal obligation to do somthing about it. Do these things have a time limit on them as it was years ago?
Thanks for any advice anyone could give me.

No-one knows what this "thing" is.

If it was a Guarantor Agreement form then you could be liable, but it doesn't seem to be asking you to pay up... it is asking for someone's whereabouts.

Ignore it.

Even if it was a Guarantor Agreement, you didn't seem to be aware of that. However, it's good to read things that we are actually signing our name to.