Dad has fairly recently bought a 2018 68 plated L405 TDV8. It is a Vogue SE and has done 30k miles if that makes any difference

It has an annoying rattle/squeak/noise that is very hard to decipher where the noise is coming from. I am convinced its in the front but strangely as a driver it does sound like it could be the rear. Yet we cannot find any piece of trim or section of leather or anything that is obviously causing this noise.

It is only a quiet noise but is extremely annoying. However the other day when looking for it he used the windscreen washers and this noise disappeared! Could it possibly be dry wipers rubbing against the windscreen? To me it was cured but they've been out in it again today and the noise is back and apparently doesn't totally go when the wiper blades are wet. I have advised they replace the wiper blades, can't hurt, and go from there.

Has anyone else experienced anything as daft as this? 2005 E60 M5
2006 L322 4.2 SC
2020 Tesla Model S Long Range
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2004 L322 4.4 Vogue, 2019 NP300 Navara, 2016 NP300 Navara, 2002 L322 4.4 HSE, 2006 (MY07) L322 S/C ,2001 330Ci Sport Track Car, 2005 650i Coupe, 2001 P38 Vogue, 2003 530i Sport Touring, 1999 P38 4.6 HSE, 2002 E39 M5, 1995 300zx TT Slicktop, 1997 M3 Evo, 1992 300zx TT Targa, 1998 323i Coupe