London F.S. Paquebot Posted at sea

Hello there,
I am intruding with a question, on behalf of a stamp acquaintance of me
:

http://i64.servimg.com/u/f64/11/54/43/10/london10.jpg

London F.S. 1933 / Paquebot / Posted at sea
F.S. means Foreign Section (London).
The stamp is a 2.5 pence one, Barbados
The destination is Switzerland.

Questions :

Did the boat deliver this letter at London Harbour, or did it deliver
it elsewhere, with despatch transfer to London Foreign Section ?

Was à Barbados stamp valid for franking on any british boat, or not ?

Any learned comment about this cover will be welcome. Thanks.

--
Cordialement,
Bruno

Sir F. A. Rien a écrit :
bc92 found these unused words:

http://i64.servimg.com/u/f64/11/54/43/10/london10.jpg

London F.S. 1933 / Paquebot / Posted at sea
F.S. means Foreign Section (London).
The stamp is a 2.5 pence one, Barbados
The destination is Switzerland.

Questions :

Did the boat deliver this letter at London Harbour, or did it deliver
it elsewhere, with despatch transfer to London Foreign Section ?

It would have been delivered into the GPO at the port of call. You'd have to
trace the ship's route to know where.

Right. Normally, this cancellation, which doesn't seem to be rare,
should (?) have been applied at the port of call. Either the port is
London, or a number of british harbours post-offices could use this
cancel ?

I fell like I am missing some point.

Many thanks all the same.

--
Cordialement,
Bruno

Sir F. A. Rien a écrit :
bc92 found these unused words:

http://i64.servimg.com/u/f64/11/54/43/10/london10.jpg

Right. Normally, this cancellation, which doesn't seem to be rare,
should (?) have been applied at the port of call. Either the port is
London, or a number of british harbours post-offices could use this
cancel ?

I fell like I am missing some point.

Either the port was the City of London or it was missed by the locals
processing the mail at whatever port the ship reached.

I believe that it would have passed through the 'foreign desk' on its way
out of the UK. Failure to cancel locally caught - or direct delivery to [put
in an ex-UK bag] the FS processing.

My thanks again.

--
Cordialement,
Bruno