What was the first name of grandfather UPL? Maybe there is another way you could honour him besides using his initial.
Names which go with
Gemma:
Gemma &
ElliotGemma &
JamesGemma &
PatrickGemma &
Paul (I know this was the middle name before, perhaps it could work as a first name?)
Gemma &
KieranGemma &
CalebGemma &
MartinGemma &
George (I don't usually like alliteration but these sound good together imo)
Gemma &
Luke