Have you heard of 14th Waffen Grenadier Division of SS? It was a Ukrainian only division serving under Nazi Germany that is
still very much worshiped in Ukraine. Hitler courted many groups for his campaign against USSR (bar polish) including Estonians (20th Waffen Grenadier Division of the SS), Latvians (15th Waffen Grenadier Division of the SS), Russians (29th Waffen Grenadier Division of the SS (1st Russian), 30th Waffen Grenadier Division of the SS (2nd Russian)), Lithuanians (Litauische Bau-Bataillonen, Litauische Sonderverbände), Albanians(21st Waffen Gebirgs Division of the SS ''Skanderbeg''), Hungarians(XVII Waffen Corps of the SS, 25th Waffen Grenadier Division of the SS ''Hunyadi'' (1st Hungarian), 26th Waffen Grenadier Division of the SS ''Hungaria'' (2nd Hungarian), 33rd Waffen Cavalry Division of the SS (3rd Hungarian)), French(33rd Waffen Grenadier Division of the SS Charlemagne), etc
The British were under constant fear of German air raids, and combined with the convoy raids, served to starve the British out. Germans kept constant bombing of London, and England in general, as late as 1945 (see V2 rockets)
Read it. It explains quite well how Germans had prepared for the invasion, and also cites many different sources. It's a good book.
They could, though. Even post-war British were forced to admit it.
To all the rest, apologies for my slight ww2 sperging. I'll try to stay on topic