"The SWP is now the largest self-styled revolutionary party in Britain, and the leading group in the International Socialist Tendency".
Alarm bell phrases are ones that trigger suspicion, something's up. In this case I'm not so sure but it's worth dwelling on "self-styled revolutionary" for a moment.
All revolutionaries, in fact all political actors are self-styled. Politics is an art and therefore subjective. Mainstream politics has an aura of objectivity because it is the politics of the state. Neo-liberalism, the current state philosophy, only appears real because in the 70s and 80s certain political actors conspired to make it real. Marxism, which at one point is a political philosophy, also claims to be a science.
In their more sober momements bourgeois advocates acknowledge the scientific aspect of Marxism. How could they not at a time like this? But Marx has to be continually undone. When he died the only mainstream paper to acknowledge the funeral was the London Times. The obituary suggested his system would die with him. How many times now has Marxism been subdued only to come back to life?
Any radical theory brought to life, especially one connected with socialism, is generally described as "self-styled". It can't possibly be objective or practical, it can only be imposed. Have you ever had that argument, "stop trying to impose your views on me"? It actually means, "stop trying to convince me of something using argument backed up by observation and/or fact".
The "self-styled" insinuation is meant to undermine. The most recent example being the self-styled Rory Carroll's reporting from Venezuela. During the last decade the Bolivarian government defied neo-liberal gravity, something clearly wrong in that!