Collusion amongst parties to fix UK elections?

I’ve just been reading the Electoral Registration and Administration Bill (HL Bill 33) (as you do) and spotted this gem:-

18 (2) “If a candidate who is the subject of an authorisation by two or more
parties under rule 6A(1B) so requests, the ballot paper shall contain,
against the candidate’s particulars, the registered emblem (or, as the
case may be, one of the registered emblems) of one of those parties.”

If I’ve read this right it means a candidate can be registered as a candidate for multiple parties. If I remember correctly this used to be limited to 2 parties. This means ‘Socialist Labour’ and ‘Labour’ members could stand for both parties. Specifying ‘two or more’ means theoretically that a candidate could have the emblems of both ‘conservative’ and ‘lib dem’ parties on their line. It allows parties to decide to not compete for votes.