...in whole or in part of any such mortgage for every £50 or fraction of £50 of the largest sum which shall at any one time have been due upon the security of such mortgage ... .. ... ... 0 5 0> And for every £50 or fraction of £50 which shall be due upon the security of...
... fraction of £50 which shall be due upon the security of such mortgage at the time of the transfer a further sum... 