CLS DAB issues - where's the Antenna Amp?

[ISA]

Hi there, new to the forum, have a UK CLS 250 2013, having issues with the DAB, dropped signal and messages - device unavailable and no reception (get this one even when I can hear the DAB radio). Can anyone advise, partic if it may be the Antenna amp and if so where it is for inspection / replacement?

 

[ash59fifty-uk]

If like the 204 I believe it’s within the heating element on the rear window