It is the period from the date that the new lease is granted to the date that the old lease would have ended (for LTT purposes) had it not been terminated.
Dyma’r cyfnod o’r dyddiad y bydd y les newydd yn cael ei rhoi i’r dyddiad y byddai’r hen les wedi dod i ben (at ddibenion Treth Trafodiadau Tir) pe na bai wedi cael ei therfynu.