Hi John !
You could ...
... ask these:
http://www.ova.org.uk/Contact.htm
... find this book:
Sidmouth: The War Years, 1939-1945
... find these books (describe all UK Luftwaffe crashes)
and look up the Index after the locations you give:
The Blitz then and now Vol. 1 to 3
As for the dates:
the Exeter raids are a possibility:
April 23, 1942
April 24, 1942
May 3, 1942
bye then,
FrankieS