OK
The most helpful answer was to upgrade the Electrum wallet to the latest build. This has indeed let me see the transaction, and now it has 5 confirmations.
Apparently my €50 of BTC is now worth only €27 - but at least the right number of BTC is appearing in the History page of Electrum.
On the other hand the Receive screen stlll shows it as Pending. Presumably after a while it will show as confirmed?
Question Someone responded that my Receive transaction in Electrum was not necessary and that I could delete it.
But without a Receive transaction, how would I get a new Receiving Address ?
(afaik it should be unique for every transaction?)