Broadway DAB aerial

DAB reception in my 2015. Broadway is a bit "hit and miss" especially when driving with the signal dropping in and out. I suspect that this is abnormal with other users not having similar problems. I also suspect that the likely cause is a poor aerial connection.
Advice please on which wing mirror houses the aerial and how to access it (to include how to extract the radio unit please. )

I believe the aerial is in the nearside mirror  but googling it brings a lot of complaints that it's not been fitted at all (by Peugeot not AS I hasten to add). My Sussex has one of these windscreen aerials fitted (presumably by a previous owner - don't know if I have one in the mirror) which gives great reception.

https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.co.uk%2Fulk%2Fitm%2F263149839523

You can buy extractors for the radio from Halfords

That might explain things! Thank you.

One other possibility - if you're not already aware - is interference from other electronic devices in the van - especially those in the cab. Possible culprits for this are USB power supplies (as used for dashcams and satnavs), USB chargers such as those you plug into a cigar lighter to charge your phone/tablet and the driver circuitry for LED lights - especially those for DRL LEDs, as they are often higher-powered than most other LEDs in a van.

It's not unusual for any of these to completely wipe out reception in the affected waveband. I've had this from a very cheap USB power adapter (so poor that it radiated audible noise as well as RF noise!) and also from an LED G4 light module in a map reading lamp.