katten.com/the-uk-government-and-hmrcs-efforts-to-clamp-down-on-promoters-of-tax-avoidance
katten.com/files/1095783_2021_06_03_frm_uk_tax_the_uk_government_and_hmrcs_efforts_to_clamp_down_on_promoters_of_tax_avoidance.pdf
How does HMRC investigate mass-marketed tax products? – Stewarts (stewartslaw.com)