16(1)All relevant intermediaries in relation to an engagement to which this Schedule applies are jointly and severally liable, subject to sub-paragraph (2), to account for any amount required under the PAYE provisions to be deducted from a deemed Schedule E payment treated as made by any of them—
(a)in respect of that engagement, or
(b)in respect of that engagement together with other engagements.
(2)An intermediary is not so liable if it has not received any payment or benefit in respect of that engagement or any such other engagement as is mentioned in sub-paragraph (1)(b).