Central locking
 

Hello world of knowledge. My 2003 R50 ( I've owned for 5 years) is all of a sudden having issues with the range of the remote central locking. With no warning it stopped working unless the key is touching the centre of the windscreen. After googling and youtubing one option was to change the control unit in the roof under the clock which I did and that was a pain in the bum as the sunroof mechanism was in the way and it was the same result only worked when key is against the glass.
So swapped back for the original. Also swapped and checked the power of the key battery first of all. Any ideas what I could try next? Thank you in advance.
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