Excel date to Numbers text format troubles

Question

I've been sent an Excel .xls document which I'm opening in Numbers '09 (2.1).
The spreadsheet has a date column which I need to be in text format as dd/mm/yyyy. I expected the original Excel document to have the dates already in text format but Numbers says the fields are 'Custom' and shows the dates in US format: 11/04/2011, even although my Mac is set to UK format. No matter, I can set the cells to text format, however that results in the date being shown as 04/11/00002011.
Where did those extra zeros in the year come from!?
How can I reformat the dates to the dd/mm/yyyy format as text?
I've tried a couple of formula to create a new column
=Year(A1)
for example and I think I could recreate the date  like that, but the cell must be text format.
DG

Answer 1

Here is the script required to peek dates from Numbers then poke them in Numbers.
--{code}
Apply this script to a Numbers table containing :
B2 : 1943/12/31 23:59
B3 : 1789/07/14
B4 : 2010/01/01 00:12
B5 : = NOW()
set myTimeZone to (do shell script ("/usr/bin/perl -le 'print( readlink(\"/etc/localtime\") =~m{zoneinfo/(.*)} )' ")) -- Perl code by Mark J. Reed.
tell application "Numbers" to tell document 1 to tell sheet 1 to tell table 1
          repeat with r from 2 to 5
                    set thenumbersdate to value of cell r of column 2
                    set value of cell r of column 3 to thenumbersdate as text
                    set thenumbersdate to my TZtoGMT(thenumbersdate, myTimeZone)
                    tell cell r of column 4
                              set format to text
                              set value to thenumbersdate as text
                    end tell
                    tell cell r of column 5
                              set format to text
                              set value to short date string of thenumbersdate
                    end tell
          end repeat
end tell
--=====
set myTimeZone to (do shell script ("/usr/bin/perl -le 'print( readlink(\"/etc/localtime\") =~m{zoneinfo/(.*)} )' ")) -- Perl code by Mark J. Reed.
set thenumbersdate to my TZtoGMT(thenumbersdate, myTimeZone)
Handlers by Nigel GARVEY
http://macscripter.net/viewtopic.php?id=36449
(* Convert an ISO-format date string to an AppleScript date. *)
on isotToDate(isot)
          set n to (text 1 thru 8 of isot) as integer
          set ASDate to (current date)
          tell ASDate to set {day, year, its month, day} to {1, n div 10000, n mod 10000 div 100, n mod 100}
          if ((count isot) > 8) then
                    set n to (text 10 thru 15 of isot) as integer
                    set ASDate's time to n div 10000 * hours + n mod 10000 div 100 * minutes + n mod 100
          end if
          return ASDate
end isotToDate
--=====
(* Transpose an AppleScript date/time from the given time zone to GMT. *)
on TZtoGMT(TZDate, TZ)
  -- The difference between TZDate when it's local and the GMT date we want is usually
  -- the same as the difference between the local date when TZDate is GMT and TZDate itself …
          set GMTDate to TZDate - (GMTtoTZ(TZDate, TZ) - TZDate)
  -- … but not around the time the clocks go forward. If the GMT obtained doesn't reciprocate to TZDate,
  -- shift to a nearby local date where the above DOES work, get a new GMT, unshift it by the same amount.
          set testDate to GMTtoTZ(GMTDate, TZ)
          if (testDate is not TZDate) then
                    if (GMTDate > testDate) then -- "Clocks forward" is towards GMT.
                              set shift to GMTDate - testDate
                    else -- "Clocks forward" is away from GMT.
                              set shift to -days
                    end if
                    set nearbyDate to TZDate + shift
                    set GMTDate to nearbyDate - (GMTtoTZ(nearbyDate, TZ) - nearbyDate) - shift
          end if
          return GMTDate
end TZtoGMT
--=====
(* Transpose an AppleScript date/time from GMT to the given time zone. *)
on GMTtoTZ(GMTDate, TZ)
  -- Subtract date "Thursday 1 January 1970 00:00:00" from the GMT date. Result in seconds, as text.
          copy GMTDate to date19700101
          tell date19700101 to set {year, its month, day, time} to {1970, 1, 1, 0}
          set eraTime to (GMTDate - date19700101)
          if (eraTime > 99999999) then
                    set eraTime to (eraTime div 100000000 as text) & text 2 thru 9 of (100000000 + eraTime mod 100000000 as integer as text)
          else if (eraTime < -99999999) then
                    set eraTime to (eraTime div 100000000 as text) & text 3 thru 10 of (-100000000 + eraTime mod 100000000 as integer as text)
          else
                    set eraTime to eraTime as text
          end if
          return isotToDate(do shell script ("TZ='" & TZ & "' /bin/date -r " & eraTime & " +%Y%m%dT%H%M%S"))
end GMTtoTZ
--=====
--{code}
Yvan KOENIG (VALLAURIS, France) samedi 5 novembre 2011 14:14:26
iMac 21”5, i7, 2.8 GHz, 4 Gbytes, 1 Tbytes, mac OS X 10.6.8 and 10.7.2
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