timestamps and dates

I'm sure this has cropped up before but I can't find the messages so sorry to
bother everyone...

I have two systems (both linux) one, let's call it A, running 7.3.1 and one, B,
7.3.2, although I think that difference is irrelevent as I show below.

Trying:

SELECT '2003 Jul 08'::timestamptz

on A gives me the expected:

'2003-07-08 00:00:00+01'

while on B I get:

'2003-07-07 23:59:00+01'

(time zone being set for the UK)

I even reran the regression tests and on B I get:

circle ... ok
date ... ok
time ... ok
timetz ... ok
timestamp ... ok
timestamptz ... ok
interval ... ok
abstime ... ok
reltime ... ok
tinterval ... ok
inet ... ok

And when I look at the output I do indeed correct results like:

SELECT '' AS to_timestamp_3, to_timestamp('1985 January 12', 'YYYY FMMonth DD');
to_timestamp_3 | to_timestamp
----------------+------------------------------
| Sat Jan 12 00:00:00 1985 PST
(1 row)

So obviously I'm missing something (and it appears not to be a version
thing). Any help?

TIA

--
Nigel J. Andrews