I don't grok the boldening. Why Unknown? Because no parliamentarian ever tried to impose "formal requirements as to subsequent amendment or repeal of legislation"?
Bradley, Ewing. Constitutional and Administrative Law (2018 17 ed). p 66 para 2.
It is worth distinguishing at this stage between formal requirements as to subsequent amendment or repeal of legislation, and statutory provisions which are intended to avoid the implied repeal rule and apply presumptions even to future legislation. The former are unknown, but there are examples of the latter, which may be thought of as a ‘soft’ form of affecting successor Parliaments (subject always to express repeal). The Interpretation Act 1978 sets numerous interpretative presumptions which apply to all legislation which both pre- and post-dates it (s 22(1)). Both the European Communities Act 1972 (s 2(1)) and the Human Rights Act 1998 (s 3) require past and future legislation to be interpreted in accordance with the principles to which they give effect.