On a quick reading, the most relevant part appears to be 118 Special restrictions on referendum expenses by permitted participants. (politics.stackexchange.com)
As the Divisional Court recognised at paragraph [29] of its judgment, «if making a donation of the kind described in paragraph 2 (1)(c) of Schedule 15 also involves incurring a referendum expense, then only permitted participants could make such donations exceeding # 10,000, and only the designation organisation could make such donations exceeding # 700,000, without contravening the rules restricting campaign spending.» (dominiccummings.com)
The Campaign to Stop Killer Robots was pleased to be able to attend this well - organized and timely conference held under the Chatham House rule, which permits participants to use information received but not to reveal the identity or affiliation of the speaker or participants. (stopkillerrobots.org)