Thanks so much everyone for all the lovely suggestions – I really appreciate everyone taking the time to reply. 
We do really like [name_f]Isabel[/name_f]. My only hesitations are that it feels quite “2000s”, and I can’t help thinking of the “is a bell” joke/connotation. I also really don’t like the nickname [name_f]Izzy[/name_f], which seems almost inevitable! For those with an Isabel/Isabelle, do people automatically shorten it to [name_f]Izzy[/name_f], or is it actually quite easy to stick with the full name?
We are also torn between the spellings [name_f]Isabel[/name_f] and [name_f]Isabelle[/name_f]. Which do you prefer and why?
More recently, [name_f]Emilia[/name_f] has crept onto our shortlist too, and even [name_f]Mia[/name_f], although I wonder if [name_f]Mia[/name_f] feels a little too different in style from [name_m]Leo[/name_m].
And then there’s Sophia… it has honestly been my favourite girls’ name since long before I ever had children. I still absolutely love it, but I’m put off by how popular it is. Is it one of those names where the popularity doesn’t really matter in real life, or would you avoid it because of that?
We just can’t seem to make a final decision! 