Interior fleet numbers.

[Liverpool Street]

Yes if you are referring to the hybrids and tridents although I'm not sure whether those black fleet numbers had already been applied on the upper saloon. Tridents definetley didn't have black fleet numbers on the upper deck previously

Indeed they didn't. Just seems they're making it easier for the bus to be reported, as no staff member has any need or requirement for the upper saloon numbers

Maybe they will come in handy after a bridge strike so they know which bus to 'stick the roof back onto' afterwards, or maybe it's for passengers wishing to report an incident to do with the vehicle who will not be passing the lower saloon fleet number on their way off  :P
Either way I would say 90% of passengers wouldn't even notice it & 85% of passengers would not even know what it is

Ha, I think you're right there -- "O.K. Madam (even though 'she's' just some Northfield Bulldog wanting to complain about the driver bringing her sprog up about the out of date WeeklySaver scratch card), do you know the vehicle fleet number?" . . "Durr, Da numba is 63 u kno." Etc etc etc

Its like people who notice it say 'what's that number for?' To which my usual response was 'I don't know to be honest' ;)

[broma1k]

Travelled on 4939 last night to Sutton & it had a fleet number upstairs & downstairs above the front windows.

[Trident 4609]

Travelled on 4939 last night to Sutton & it had a fleet number upstairs & downstairs above the front windows.

I might be wrong but BC's and PB's newest E400's my have had those fleet numbers since new?

[Liverpool Street]

Travelled on 4939 last night to Sutton & it had a fleet number upstairs & downstairs above the front windows.

I might be wrong but BC's and PB's newest E400's my have had those fleet numbers since new?

Correct.