Yes that is correct. The imported file had only 1 (one) key.
That could be problematic... if you only have one key, then you won't have any keys for change addresses
From the main address (starts with a 1) and under the History Tab in Electrum there are six imputs with green checkmarks in front of the date.
In Electrum... with the 6
transactions that you see with the green checkmarks... are the values shown in the "amount" column displayed in Red colour? Red = outgoing coins.
What is the balance shown in the bottom left corner?
When I click on one of these they reveal quite a lot of other information. Would the "change address be in there?
Yes, you should be able to see the "Outputs" box that will list all the outputs created by the transaction. If there is more than one address shown in "Outputs", then one of them will be the change address. Unfortunately, as I mentioned above, if you only have 1 key imported, then none of the "change" addresses (and their private keys) will be loaded into your wallet.
So you will not have access to any of the coins in any change addresses (if any) unless you can find the keys for those addresses.