But for some reason I cannot send the last remaining bit of bitcoin, and this is despite me keeping the inputs to 15, as stated on the transaction window in electrum. Would anyone know why? I'm not sure what has to be done differently. It says 'Inputs (15)'.
Are you getting any error message when spending the last batch of inputs?
If 20 inputs have worked, then 15 shouldn't be a problem.
Also, try to enable the log and see if there's an error related to the issue: "
Tools->Preferences->Write logs to file", restart Electrum.
Reproduce the issue in that session, then you can disable logging again; the logs will be saved in "
logs" folder inside
Electrum data directory.