I am obviously doing something stupid again, but I don't suppose I am
the only stupid person in the world.

Is this just me that can't look up a bus route map by bus route on the
TfL site?

One is invited to put something in a text field, with the wording

"Find bus routes
Route no, postcode, address, landmark or station"

No matter what route I put in, even if I put in "route n", it takes me
to number n London Road somewhere in the London area.

Eg if I am looking for the 25 and enter "25" it takes me to 25 London
Road, Epsom, with a map of route 406. If I put in "route 25" it takes
me to 25 London End, Beaconsfield with a map of route 331.