The Leader has appeared on Richard and Judy (the cheery weekday afternoon TV show on ITV) on more than one occassion to talk about Join Me. A short film of Danny was also made of him giving out ice creams, etc. in a seaside location.
Richard (Madely) and Judy (Finnegan) handed over their passports to Danny live on air.
They've also slipped into Join Me Top Trumps as Joinees Madely and Finnegan, though whether they ever refer to themselves by these Joinee names is unknown.
There's a more thorough history of the two TV presenters at Wikipedia.