With any self-respecting organization that has endured across multiple generations there are the so-called “Glue Guys,” those whose total contributions to the institution in question span from one epoch to another.
As you might imagine Doctor Who has had their share of these people from the more obvious, Nick Courtney and especially Liz Sladen jump to mind, but there are other, slightly more prosaic examples.
The Tour has its own ‘Mystery Guest,’ someone who surprisingly happened to fill the longest gap Doctor Who has ever faced once in 1999 with the tangentially related ‘Curse of the Fatal Death’ Children in Need sketch and then again in 2003 with the BBCi production of ‘Scream of the Shalka.’
The real reason Richard E Grant is an underappreciated Glue Guy is due to the length and breadth of his career, from ‘Withnail & I’ with Paul McGann 30 years ago up to the present day, and this has given him the opportunity to meet, and act with, a fair number of Who alumni through the years.
Both Gluey and Who-ey (pun sadly intended).