Very nice! I’ve got lots of these figures myself - a ‘finished’ English army and a Scots army about 2/3 done.
I guess the reference to manufacturers closing down might refer in part to QRF, perhaps Fighting 15s as well?
I am a fan of the Donnington New Era range - if you have gaps you might find their Late Medievals fit well. There are quite a lot of models across the Wars of the Roses, Swiss, Burgundians etc that I use for Scottish and English men at arms in plate, that would blend fine with QRF.
Their horse are good too but not in the same unit as QRF if you’re a perfectionist.