Amelia - not keen. Don't like the 'mealy' sound. Very popular
Emily - quite like it. Very popular.
Ella - like it.
Eva - love it.
Emma - it's ok
Eliza - it's ok
Zara - love it
Pippa - like it but would probably use Philippa for full, even though less nice
Amber - love it - maybe just because I teach a gorgeous 12 year old one
Matilda - love it
Sophia - really like it
Jack - love it though very popular
Alfie - quite like it. Very popular
Oscar - love it
Lucas - quite like it
Daniel - quite like it
Theo (DH not keen) - love it but no good if you DH not keen
Hugo (we both like but DH worries it's too posh) - not keen
Elliot - love it
Flynn - love it
From your lists I think I would go for one of:
Zara Emma
Amber Laura
Matilda Margaret
Elliot George (unless worried about George Elliot)
Jack William
Oscar William
Other suggestions -
Alice, Alexa, Cassandra, Callie, Emmeline, Erin, Freya, Georgia, Hannah, Isla, India, Jessica, Julia, Katie, Lara, Layla, Lydia, Luna, Martha, Maisie, Mia, Madeleine, Miranda, Naomi, Olivia, Phoebe, Rosie, Ruby, Sara, Sadie, Saskia, Thea, Verity
Archie, Aidan, Caleb, Dominic, Ethan, Felix, Fergus, Finley, Harry, Isaac, Jamie, Jared, Luca, Logan, Micah, Noah, Nicholas, Owen, Patrick, Reuben, Samuel, Thomas, Zachary