On Mar 1, 4:51*pm, Adrian wrote:
"Matt Wheeler" gurgled happily, sounding
much like they were saying:

Will wait for someone to confirm, but at a guess, it may be an
Amersham/Chesham to Watford service that weekend. This would seem
likely, given an earlier closure on 27/28 June is listed as Harrow on
the Hill to Amersham, Chesham & Watford.

That was my first thought, but for the "/Rickmansworth". That'd imply
that there's nothing south of Ricky on the Amersham branch, to my mind.

shrug

Reads to me that it is nothing Harrow - Croxley or Harrow -
Rickmansworth. So a Watford - Amersham shuttle fits in fine.