On an action-packed morning for the British team in Chartres, Miley stood out by posting 2:08.44minutes in the 200m medley heats to rank just 0.04 seconds behind Katinka Hosszu.
Hosszu's Hungarian team-mate Zsuzsanna Jakabos placed third a further 0.14 back while 16-year-old Brit Siobhan-Marie O'Connor put in an impressive swim to rank fourth fastest.
Britain had two more swimmers in the top eight, Aimee Willmott in seventh and Sophie Smith in eighth, however, with only two per nation allowed in the final, they cruelly missed out.
That would serve to aid Miley's bid for a fifth European short course medal having won bronze in the 200m medley in 2011 and 2009 and silver and gold in the 400m medley the same years respectively.
Miley had already been in the pool before her 200m medley swim, tackling the 50m breaststroke heats however she did not make it to the semi-finals after clocking 32.21 for 20th overall.
And Miley's morning session ended as it started with the British 4x50m freestyle relay team of herself, Smith, Lauren Quigley and O'Connor being disqualified in the heats.
Meanwhile back in the 50m breaststroke heats Molly Renshaw suffered a similar fate to Miley with her time of 32.96 putting her seven places down on her in 27th.
There was however much to cheer for four other members of the British squad in France, firstly Quigley and Karley Mann who reached the 100m backstroke semi-finals.
Quigley, 17, recorded a time of 58.93 for eighth overall in the heats while Mann benefited from France having three swimmers in the top 16 after clocking 1:00.58 for 17th.
Antony James was 12th fastest in the 100m butterfly in 52.58 while Craig Benson finished in exactly the same position in the 100m breaststroke, both progressing from the heats to the semi-finals.
However there was to be no such advancing for Lewis Coleman and Thomas Haffield in the men's 200m medley heats or Marco Loughran, Calum Jarvis, Craig McNally and Joseph Patching in the 200m backstroke equivalent.
Jack Burnell was 22nd in the 400m freestyle while 19-year-old Lucy Spencer missed out on a place in the semi-finals of the 100m freestyle by the narrowest of margins.
Spencer clocked a time of 55.73 for 22nd overall but once the limitations on nations progressing through to the semi-finals were taken into account she was 0.01 shy of advancing.
And the British men's 4x50m medley relay team of Loughran, Benson, James and Jarvis also failed to make it out of the heats after ranking tenth in 1:38.69.