6. An authorised officer may only certify seed potatoes as pre-basic seed potatoes if, following an official examination, the officer is satisfied that the seed potatoes meet the requirements specified in columns 2, 3 and 4 of Table I in Schedule 2 corresponding to at least one of the Union grades specified in column 1 of that Table.
7. An authorised officer may not certify seed potatoes as pre-basic seed potatoes unless the officer is satisfied that the land on which the seed potatoes are or were grown—
(a)has, following an official examination performed prior to the planting of the crop, been found not to be contaminated with Potato Cyst Nematode (Globodera spp. infesting potatoes);
(b)is not land notified as infested with Potato Cyst Nematode (Globodera spp. infesting potatoes) under paragraph 7 of Schedule 15 to the Plant Health (Scotland) Order 2005;
(c)has not been found to have been contaminated with Potato Cyst Nematode (Globodera spp. infesting potatoes) for at least 6 years prior to the planting of the crop; and
(d)has not been used for growing potatoes at any time during the 7 years immediately preceding the planting of the crop.
8. An authorised officer may not determine the seed potatoes as meeting the requirements of Union grade PBTC, if the immediately succeeding crop produced from those potatoes is likely to contain—
(a)plants of another variety; or
(b)plants infected by virus.
9. An authorised officer may not determine the seed potatoes as meeting the requirements of Union grade PB, if, in relation to the immediately succeeding crop produced from those potatoes, the number of growing plants which—
(a)deviate from variety and type, is likely to exceed 0.01% of the total number of plants in that crop; or
(b)show symptoms of any virus attributable to infection in the mother crop, is likely to exceed 0.5% of that total number.