2006 laguna beeping

Ive a 2006 laguna top spec. Morning times,get in car no issues, no warning lights. Turn on engine,lights on,pull away and the damn beeping starts. 30 ish seconds oc a low pitch followed by 30 ish seconds of a louder higher pitch. Today it stopped after the higher pitch,the other day it repeated the two pitches 3 times.

No warning signals anywhere...

Its loud enough to overide the sterio

Any ideas short of paying Renault prices for a diagnostic link up.

Thanks

2006 laguna beeping