BKM402775 | Banking surcharge: definition of banking company: excluded entities: other companies
From HM Revenue & Customs · Banking Manual
An entity is also an excluded entity if it is a:
friendly society
credit union
a building society
A building society remains a banking company even though it is an excluded entity this is because a building society as defined in BKM402200 will always be a banking company. Unlike a company, it does not need to meet conditions A to E to be a banking company.