Catching up on the discussion. Have checked my Aero series 5 and definately no amp under the seats or anywhere else in my opinion. So the 50 watts peak from Parrot unit is just about enough for my needs.
I had a look at the Pioneer EVO64DAB Radio and it looks good, what about the Sony equivalent which fits in a single DIN and screen can be at top/middle/bottom of unit plus swivel, seems cheaper and no need for special cage - link below
https://www.halfords.com/technology/car-audio/apple-carplay/sony-xav-ax8050d-car-stereo-with-apple-carplay-and-android-auto-342958.html?cm_mmc=Google+PLA-_-Motoring%3ETechnology%3ECar+Audio%3EApple+Carplay-_-Motoring%3ETechnology%3ECar+Audio%3EApple+Carplay-_-342958&istCompanyId=b8708c57-7a02-4cf6-b2c0-dc36b54a327e&istFeedId=62b447cf-331e-4fec-a47a-9985ff72d404&istItemId=iiaiwxiit&istBid=t&_$ja=tsid:|cid:16710940973|agid:|tid:|crid:|nw:x|rnd:17849894554311104205|dvc:c|adp:|mt:|loc:9046138&gclid=CjwKCAjw6fyXBhBgEiwAhhiZsj4wHRxwSuFN4iKrn2_k19x5dB7nxDuCuPNHhbU5G8NG93frh7pfEBoCn2gQAvD_BwE
Apologies for long URL but blame Halfords. I have had quotes of £395 to replace Parrot so £400 doesn't sound unreasonable, I am still not sure how to get access to the P.arrot to remove it though
