Thanks for responding to my initial request on feedback for Tell Sid. I have already forwarded some of it to Mr "Tell Sid" who created the campaign but he's a pretty busy man so I think you'll have to wait for an answer to some of these questions - I will post it when I get it though.
The reason behind the selloff, as far as I know, was because British Gas was reorganising into a new corporate entity, since people were switching from town gas to north sea gas and this was the perfect opportunity to publicise the new company.
Maybe I'm wrong... anyway for all of you on this thread, let me quote you from the questions and answers I got from the person behind the campaign (very interesting!):
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As an overview, what struck me most about this campaign (and you may wish to comment on this) was the sheer scale - at one point in time, it seemed as if everywhere you went in Britain, people were looking for Sid through bill***, TV ads and etc. !! I
remember being very impressed by the scale and sheer 'overkill' aspect and have since read that a not inconsiderable 40 million quid went into it. So first question:
1. How did you feel when you went about your daily business and saw your ad campaign capture the nation's imagination in all these forms ? Did it exceed your expectations ? And did your nearest and
dearest colleagues/friends/family make funny comments> about you finding him ?
THIS WAS AT THE HIGH POINT OF THE EIGHTIES [GREED IS GOOD - Gordon Gecko]
THATCHER REIGNED, THE CITY WALKED ON WATER AND AD AGENCIES COUlD DO ANYTHING
[Saatchi was yet to bid for the Midland Bank!] THE ONLY PREVIOUS
PRIVATISATION WAS BT AND WE THOUGHT THAT WAS PRETTY SAFE AND BORING
CREATIVELY. WE SET OUT TO PROVE THAT SHARES COULD BE MASS MARKETED - TO THE
HORROR OF MANY IN THE CITY, AND BID FOR THE BUDGET TO DO IT WITH. THE
GOVERNMENT HAD EARMARKED 17MILLION BUT WE WENT BACK AND SAID WE WANTED 26.
THAT WAS STILL AT THAT TIME THE LARGEST UK CAMPAIGN EVER ESPECIALLY WHEN YOU
THINK THAT IT WAS ALL SPENT IN JUST THREE MONTHS. WE SET OUT FOR BLANKET AWARENESS, INFORMATION AND MOTIVATION. AND THAT'S
WHAT IT FELT LIKE. AMAZING AND WE WERE DOING IT. NO SINGLE ACHIEVEMENT
AFTER THAT IN ADVERTISING FELT AS GOOD.
2. Can you tell me how the idea of "Tell Sid" was dreamed up. Was it a pub lunch or an anecdote or just something that literally just came to you and you thought "this is a gamble worth taking" ? What prompted you to decide on it for definite ?
OUR BACKS WERE TO THE WALL. WE'D BLAGGED ALL THE MONEY NEEDED TO DO AN
EFFECTIVE CAMPAIGN AND HADN'T CRACKED THE BIG IDEA - BLOODY EMBARRASSING,
THE POSSIBILITY OF CLUBBING THE NATIONAL CONSCIOUSNESS TO DEATH WITH TURGID
WORK. WE'D HAD CREATIVE TEAMS LOCKED AWAY IN HOTELS OVER EASTER AND COULDN'T
GET IT.AFTER ABOUT THE THIRD FIASCO WITH THE CLIENT 3 OF US - ANNIE ROTHWELL -
PLANNING DIRECTOR, RUPERT HOWELL - ACCOUNT HANDLER AND I WENT TO A BAR AND
OVER A DRINK AGREED A NEW BRIEF. A WEEK LATER RUPERT CAME INTO MY OFFICE
AND SAID 'I THINK WE'VE GOT IT'. DREAMED UP BY A BRILLIANT CREATIVE TEAM
JEANNIE WILLIS AND TREVOR MELVILLE. SID WAS ON THE TABLE. WE THEN HAD TO
SELL IT TO THE CLIENT INCLUDING THE ENERGY MINISTER PETER WALKER. AFTER IT
WAS ALL OVER HE SAID 'I HAVE TO DECLARE AND INTEREST - I HAVE A BROTHER
CALLED SIDNEY!'
3. I seem to remember one advert which struck me in particular, where a guy looks over a cliff or is somewhere remote, and says something like "Sid... is
that you
" Can you shed any more light on that one ?
THAT WAS THE FINAL AD IN THE RUNNING SERIES AND JUST AS THE PUBLIC BELIEVED
THEY WERE ABOUT TO SEE SID, HE DISAPPEARED INTO THE MIST AGAIN.
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Hope you enjoyed this folks - please give more feedback! 
Cheers, UKexpat