Bleeping again!

After listening to the bleep yesterday and some of last night it has been quiet all day until two minutes ago! If its on a timer I dont remember what...or how... I thought it was sorted but clearly not. I am downstairs just now and it sounds very loud so I will go upstairs soon. I have no idea whats causing this...but its very annoying...and thats an understatement! Yesterday it went on until early this morning! Once it had stopped I thought I had cured it...but no here we are again. Yesterday nothing I thought of worked so I am trying to work out what it was for originally...Light? ....something I cant work out! I have no idea what to do now...nothing worked yesterday! Since writing that it has stopped again...I dont know how long for! I am upstairs in my ditting room...and so far so good. Fingers crossed time!