Can confirm EastEriq's worked for me. In /mnt/ext1/system/language/en.txt I have this:
English
@koreader=KOReader
@pbterm=PB Term
@Jailbreak=Jail Break
@PbDbFixer= Database Fix
Still trying with the custom images
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If and when this is solved (thanks for all the replies and help everyone) I will create a git hub project to document all of this