To jog memories here are a few pieces to help things along.
BJL made many pretty enamel and marcasite brooches and earrings. Looking at the style and findings of many of their pieces - they made jewellery from the 1920s up to the 1960s at least. Not only the enamel ones but a range of vintage necklaces, brooches, earrings and bracelets. Some of the jewellery was signed with block lettering BJL on a square plaque. But there are unsigned ones to look for.
Both of these brooches are from BJL as size, findings same and they appear to match in style.
Which leads me to the infamous vintage lily brooch in enamel and marcasite. Made in numerous colourways. Is this by BJL? The backs are very similar to the ones that are signed BJL. The lily brooches are in both pot metal with a C shaped fastening. Also they are available with rhodium plated backs and with a safety fastening. SO DO YOU HAVE this brooch with a signature? Please share any information.