advice please

[totallylost]

This is going to sound confused but I will try to make it as simple as possible.
A person who became very involved with my accuser prior to the allegations being made used to abuse me and made threats something like this would happen. There are solicitor and doctor records to prove this. This however was many years ago.
Am I right in saying this will not be able to be used at my trial - the police although they have been told of this have not followed up any lines of investigation that can confirm this.

[Peter1975]

You really need to ask a solicitor TL, it's not clear whether you are asking if this person could be a witness or if what they said years ago could be introduced as hearsay (gossip) -

If it's the former then yes, providing they have evidence that is relevant to your case. If the latter then probably not but you should always check with a solicitor.

The police are notorious for not following up anything that helps the defence but sometimes, what they deem irrelevant or not worth bothering with turns out to be just that, but then even a stopped clock is right twice a day..