Thanks Dave, OH saw a double DIN, quite new and quite slick touchscreen cd/blutooth maybe even DVD palyer (we don't need a DVD player in the hearse!) head unit that had android connectivity for your smart phone and wanted one, it did look smart and would be good for our french adventures in the hearse, but they seem quite expensive and tricky to install.
I've been looking around online and see that some have used a 780 radio trim piece, cut the middle out and hey presto! You have a double DIN space, it does mean relocating the cigarette lighter socket, removing and relocating the overdrive relay and moving the whole fuseboard back a little - i'm thinking this is quite a lot of effort! Even
if the trim piece can be found, which is unlikely these days I think. The thread I saw was
here.