6E+WWhere under an agreement between the landlord and the tenant of the holding (not being an agreement expressed to take effect as a new contract of tenancy between the parties) provision is made for adjustment of the boundaries of the holding or for any other variation of the terms of the tenancy, exclusive of those relating to rent, then, unless the agreement otherwise provides—
(a)that provision shall for the purposes of sub-paragraph (1) of paragraph 4 above be treated as not operating to terminate the tenancy, and accordingly as not resulting in the commencement of a new contract of tenancy between the parties, and
(b)any increase or reduction of rent solely attributable to any such adjustment or variation as aforesaid shall be disregarded for the purposes of paragraph (b) of that sub-paragraph.